ada: Fix for compiler crash on function return with Relaxed_Finalization parts

ada: Fix for compiler crash on function return with Relaxed_Finalization parts

The compiler crashes on compiling a return statement of a function whose result
type has a component whose type is specified with Relaxed_Finalization. The
compiler was attempting to retrieve a nonexistent BIP_Collection extra formal
from the enclosing function, which may not exist in the case of result types
with Relaxed_Finalization.

gcc/ada/ChangeLog:

	* exp_ch3.adb (Build_Heap_Or_Pool_Allocator): Test not Has_Relaxed_Finalization
	as a guard against retrieving BIP_Collection formal (and related code).