[Ada] Crash on predicate in full view in a generic unit

[Ada] Crash on predicate in full view in a generic unit

This patch fixes a compiler abort on a dynamic predicate applied to the
full view of a type in a generic package declaration, when the
expression for the predicate is a conditionql expression that contains
references to components of the full view of the type.

2019-09-19  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch13.adb (Check_Aspect_At_End_Of_Declarations): Simplify
	handling of expressions in predicates when the context is a
	generic unit.

gcc/testsuite/

	* gnat.dg/predicate14.adb, gnat.dg/predicate14.ads: New
	testcase.

From-SVN: r275939