ada: Implement Aspects as fields under nodes

In the previous implementation Aspect Specifications were
stored in a separate table and not directly under each node.
This implementation included a lot of extra code that needed
to be maintained manually.

The new implementation stores Aspect_Specfications as a syntactic
field under each node. This removes the extra code that was needed
to store, traverse and clone aspects for nodes.

gcc/ada/

	* aspects.adb (Exchange_Aspects): Removed. This method was
	typically called after a Rewrite method. Now since the Rewrite
	switches the aspects between the new and the old node it is no
	longer needed.
	(Has_Aspects): Converted to a utility method that performs the same
	before as the previous Has_Aspects field did. Meaning it shows whether
	a node actually has aspects or not.
	(Copy_Aspects): New utility method that performs a deep copy of the
	From nodes aspects.
	(Aspect_Specfications): Removed. No longer needed. Replaced
	by the primitive operation for the Aspect_Specification fields.
	(Set_Aspect_Specifications): Likewise.
	(Aspect_Specifications_Hash_Table): Remove the table and all the
	utility methods for storing the old aspects.
	* aspects.ads: Likewise.
	* atree.adb (Copy_Separate_Tree): Remove custom code for aspects.
	(New_Copy): Likewise.
	(Replace): Likewise.
	(Rewrite): Likewise.
	* exp_ch3.adb (Expand_N_Object_Declaration): Keep the aspects from the old node.
	* exp_ch6.adb (Validate_Subprogram_Calls): Previously aspects were ignored
	because they were not on the tree. Explicitly ignore them here
	when traversing the tree.
	* exp_unst.adb (Build_Tables): Likewise
	* gen_il-fields.ads: Remove Has_Aspects and add
	Aspect_Specifications fields.
	* gen_il-gen-gen_nodes.adb: Add Aspect_Specification fields
	for all nodes that can have aspects. Additionally add
	Expression_Copy for Aspect_Speficiations to avoid reusing
	the Associated_Node for generic instantiation and aspect
	analysis.
	* ghost.adb (Remove_Ignored_Ghost_Node): Remove call to Remove_Aspects.
	The rewritten node is a Null_Statement that cannot have aspects
	and there is not anything to gain from removing them from the
	Orignal_Node of N since it technically is not part of the active
	tree.
	* inline.adb (Process_Formals_In_Aspects): Simplify code for node traversal.
	* par-ch13.adb: Avoid setting the parent explicitly for the
	Aspect_Specifications list. This is done explicitly in the setter.
	* par-ch6.adb: Likewise.
	* par_sco.adb (Traverse_Aspects): Handle early return.
	* sem_ch10.adb: Simplify code for Analyze_Aspect_Specifications.
	* sem_ch11.adb: Likewise.
	* sem_ch12.adb (Analyze_Formal_Derived_Interface_Type): Keep the aspects from
	the orignal node after rewrite.
	(Analyze_Formal_Derived_Type): Likewise.
	(Analyze_Formal_Interface_Type): Likewise.
	(Analyze_Formal_Object_Declaration): Simplify code for
	Analyze_Aspect_Specifications.
	(Analyze_Formal_Package_Declaration): Likewise.
	(Analyze_Formal_Subprogram_Declaration): Likewise.
	(Analyze_Formal_Type_Declaration): Likewise.
	(Analyze_Generic_Package_Declaration): Remove Exchange_Aspects.
	The new node already has the correct aspects after the rewrite.
	Also simplify code for Analyze_Aspect_Specifications.
	(Analyze_Generic_Subprogram_Declaration): Likewise.
	(Analyze_Package_Instantiation): Simplify code for
	Analyze_Aspect_Specifications.
	(Build_Instance_Compilation_Unit_Nodes): Remove explicit copy of
	aspects that is no longer needed.
	(Save_References): Update the traversal code to handle
	Aspect_Specifications in the tree.
	(Copy_Generic_Node): Remove explicit copy for aspects. New_Copy
	took care of that already.
	* sem_ch13.adb (Analyze_Aspect_Specifications): Add early return to simplify
	code for its calls. Avoid reusing the Entity(Associated_Node)
	field for storing the original expression. Instead use the
	new Expression_Copy field since Entity(Associated_Node) is
	also used in generic instantiation.
	(Analyze_Aspects_On_Subprogram_Body_Or_Stub): Simlify call
	to Analyze_Aspect_Specifications.
	(Check_Aspect_At_End_Of_Declarations): Use Expression_Copy
	instead of Entity.
	(Check_Aspect_At_Freeze_Point): Likewise.
	* sem_ch3.adb: Simplify calls to Analyze_Aspect_Specifications.
	* sem_ch6.adb (Analyze_Abstract_Subprogram_Declaration): Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Expression_Function): Keep the aspects from the
	original node after a rewrite.
	(Analyze_Generic_Subprogram_Body): Remove Exchange aspects
	that is no longer needed. Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Null_Procedure): Keep the aspects from the
	original node after a rewrite.
	(Analyze_Subprogram_Body_Helper): Simplify calls to
	Analyze_Aspect_Specifications.
	(Analyze_Subprogram_Declaration): Likewise.
	* sem_ch7.adb (Analyze_Package_Body_Helper): Remove Exchange aspects
	that is no longer needed. Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Package_Declaration): Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Private_Type_Declaration): Likewise.
	* sem_ch8.adb: Simplify calls to
	Analyze_Aspect_Specifications.
	* sem_ch9.adb (Analyze_Entry_Body): Simplify call to
	Analyze_Aspects_On_Subprogram_Body_Or_Stub.
	(Analyze_Entry_Declaration): Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Protected_Body): Likewise.
	(Analyze_Protected_Type_Declaration): Likewise.
	(Analyze_Single_Protected_Declaration): Keep the aspects from
	the original node after a rewrite. Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Single_Task_Declaration): Likewise.
	(Analyze_Task_Body): Simplify call to
	Analyze_Aspect_Specifications.
	(Analyze_Task_Type_Declaration): Simplify calls to
	Analyze_Aspect_Specifications.
	* sem_dim.adb: Remove explicitly setting the parents
	for the Aspect_Specification list.
	* sem_disp.adb: Remove the with that is no longer
	required since Aspect_Specifications is a node operation now.
	* sem_util.adb (Copy_Node_With_Replacement): Remove explicit code for aspects.
	* treepr.adb (Print_Field): Remove the version that was used for printing
	aspects.
	(Print_Node): Remove aspect specific code.