ada: Use static references to tag in more cases for interface objects
This extends the use of static references to the interface tag in more cases
for (class-wide) interface objects, e.g. for initialization expressions that
are qualified aggregates or nondispatching calls returning a specific tagged
type implementing the interface.
gcc/ada/
* exp_util.ads (Has_Tag_Of_Type): Declare.
* exp_util.adb (Has_Tag_Of_Type): Move to package level. Recurse on
qualified expressions.
* exp_ch3.adb (Expand_N_Object_Declaration): Use a static reference
to the interface tag in more cases for class-wide interface objects.