ada: Fixup one more pattern of broken scope information

ada: Fixup one more pattern of broken scope information

When an array's initialization contains a `others =>` clause with an
expression that involves finalization, the resulting scope information
is incorrect and can cause crashes with backend (i.e. gnat-llvm) that
also use unnesting. The observable symptom is a nested object
declaration (created by the compiler) within a loop wrapped in a
procedure created by the unnester that has incoherent scope information:
its Scope field points to the scope of the procedure (1 level too high)
and is contained in the entity chain of some entity nested in the
procedure (correct).

The correct solution would be to fix the scope information when it is
created, but this revealed too large of a task with many interaction
with existing code.

This change adds another pattern to the Fixup_Inner_Scopes procedure to
detect the problematic case and fix the scope, "after the facts".

gcc/ada/

	* exp_ch7.adb (Unnest_Loop::Fixup_Inner_Scopes): detect a new
	problematic pattern and fixup the scope accordingly.