ada: Fix internal error on quantified expression with predicated type

ada: Fix internal error on quantified expression with predicated type

The problem is that the special function created by the compiler to check
the predicate does not inherit the public status of the type, because it
is generated as part of the freezing of the quantified expression, which
occurs from within a couple of intermediate internal scopes.

gcc/ada/

	* sem_ch13.adb (Build_Predicate_Function_Declaration): Adjust the
	commentary to the current implementation.
	* sem_util.ads (Current_Scope_No_Loops): Move around.
	(Current_Scope_No_Loops_No_Blocks): New declaration.
	(Add_Block_Identifier): Fix formatting.
	* sem_util.adb (Add_Block_Identifier): Likewise.
	(Current_Scope_No_Loops_No_Blocks): New function.
	(Set_Public_Status): Call Current_Scope_No_Loops_No_Blocks instead
	of Current_Scope to get the current scope.