ada: Cleanup preanalysis of static expressions (part 6)

ada: Cleanup preanalysis of static expressions (part 6)

Rename Preanalyze_Spec_Expression as Preanalyze_And_Resolve_Spec_Expression,
Preanalyze_Assert_Expression as Preanalyze_And_Resolve_Assert_Expression,
and Preanalyze_Default_Expression as Preanalyze_And_Resolve_Default_Expression;
cleanup the version of Preanalyze_Assert_Expression without context type.

gcc/ada/ChangeLog:

	* sem.ads: Update reference to renamed subprogram in documentation.
	* sem_ch3.ads (Preanalyze_Assert_Expression): Renamed.
	(Preanalyze_Spec_Expression): Renamed.
	* sem_ch3.adb (Preanalyze_Assert_Expression): Renamed and code cleanup.
	(Preanalyze_Spec_Expression): Renamed.
	(Preanalyze_Default_Expression): Renamed.
	* contracts.adb: Update calls to renamed subprograms.
	* exp_pakd.adb: Ditto.
	* exp_util.adb: Ditto.
	* freeze.adb: Ditto.
	* sem_ch12.adb: Ditto.
	* sem_ch13.adb: Ditto.
	* sem_ch6.adb: Ditto.
	* sem_prag.adb: Ditto.
	* sem_res.adb (Preanalyze_And_Resolve): Add to the version without
	context type the special handling for GNATprove mode provided by
	the version with context type; required to cleanup the body of
	Preanalyze_Assert_Expression.