atree.adb: Set Error_Posted in Error node, helps error recovery.

	* atree.adb: Set Error_Posted in Error node, helps error recovery.

	* par-endh.adb (Output_End_Expected): We should also not test
	Error_Posted on the Error node, since now it is always set.

	* cstand.adb (Create_Standard): Set Etype of Error to Any_Type
	to help error recovery. Part of general work on 9407-004.

	* par.adb: Add ??? for misuse of error

	* sem_res.adb:
	(Resolve): Defend against Error, fixes 9407-003.
	(Resolve_Discrete_Subtype_Indication): Defend against Error.

	* sinfo.ads (N_Error): Now has Etype field (which will be set
	to Any_Type to help error recovery).

From-SVN: r46077