c++: Make static init generation more consistent

The end-of-compilation static init code generation functions are:

* Inconsistent in argument ordering (swapping 'is-init' and 'priority',
  wrt each other and other arguments).

* Inconsistent in naming. mostly calling the is-init argument 'initp',
  but sometimes calling it 'constructor_p' and in the worst case using
  a transcoded 'methody_type' character, and naming the priority
  argument 'initp'.

* Inconsistent in typing.  Sometimes the priority is unsigned,
  sometimes signed.  And the initp argument can of course be a bool.

* Several of the function comments have bit-rotted.

This addresses those oddities.  Name is-init 'initp', name priority
'priority'.  Place initp first, make priority unsigned.

	gcc/cp/
	* decl2.cc (start_objects): Replace 'method_type' parameter
	with 'initp' boolean, rename and retype 'priority' parameter.
	(finish_objects): Likewise.  Do not expand here.
	(one_static_initialization_or_destruction): Move 'initp'
	parameter first.
	(do_static_initialization_or_destruction): Likewise.
	(generate_ctor_or_dtor_function): Rename 'initp' parameter.
	Adjust start_objects/finish_obects calls and expand here.
	(generate_ctor_and_dtor_functions_for_priority): Adjust calls.
	(c_parse_final_cleanups): Likewise.
	(vtv_start_verification_constructor_init): Adjust.
	(vtv_finish_verification_constructor_init): Use finish_objects.