[Ada] Extend static functions

[Ada] Extend static functions

gcc/ada/

	* inline.adb, inline.ads
	(Inline_Static_Expression_Function_Call): Renamed
	Inline_Static_Function_Call.
	* sem_ch13.adb (Analyze_Aspect_Static): Allow static intrinsic
	imported functions under -gnatX.
	* sem_util.ads, sem_util.adb (Is_Static_Expression_Function):
	Renamed Is_Static_Function.
	(Is_Static_Expression_Function_Call): Renamed
	Is_Static_Function_Call.
	* sem_ch6.adb, sem_elab.adb, sem_res.adb: Update calls to
	Is_Static_Function*.
	* sem_eval.adb (Fold_Dummy, Eval_Intrinsic_Call, Fold_Shift):
	New.
	(Eval_Call): Add support for intrinsic calls, code refactoring.
	(Eval_Entity_Name): Code refactoring.
	(Eval_Logical_Op): Update comment.
	(Eval_Shift): Call Fold_Shift. Update comments.
	* par-prag.adb (Par [Pragma_Extensions_Allowed]): Set
	Ada_Version to Ada_Version_Type'Last to handle
	Extensions_Allowed (On) consistently.
	* opt.ads (Extensions_Allowed): Update documentation.
	* sem_attr.adb: Update comment.
	* doc/gnat_rm/implementation_defined_pragmas.rst: Update
	documentation of Extensions_Allowed.
	* gnat_rm.texi: Regenerate.