ada: Fix pessimization of some CW objects initialized with function call

ada: Fix pessimization of some CW objects initialized with function call

The recent removal of the unconditional call to Remove_Side_Effects on the
expression of an object declaration or an allocator with a class-wide type
has introduced a pessimization in the former case for function calls that
return a specific tagged type, because the object ultimately created on the
primary stack has changed from being of a specific tagged type to being of
the class-wide type, the latter type always formally requiring finalization.

With the current finalization machinery, this means that a dispatching call
to the Deep_Finalize routine is generated, which is unnecessary.  Although
this is a generic finalization issue with class-wide objects, this restores
the previous behavior in this case to fix the pessimization for now.

gcc/ada/

	* exp_ch3.adb (Expand_N_Object_Declaration): For a class-wide non-
	interface stand-alone object initialized by a function call, call
	Remove_Side_Effects on the expression to capture the result.