[Ada] Fix position of subprogram body generated for static predicate

[Ada] Fix position of subprogram body generated for static predicate

2019-07-05  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* sem_ch13.adb (Build_Predicate_Functions): If a subtype that
	carries a static predicate aspect is frozen immediately after
	its declaration, ensure that the generated function body created
	for predicate checking is inserted after the corresponding
	subprogram declaration, which is created at the point the
	declaration is elaborated.

From-SVN: r273122