[Ada] Fix fallout of change in equality for untagged record types

[Ada] Fix fallout of change in equality for untagged record types

The problem is that the resolution of expanded names implicitly assumes
that the visible and private homonyms in a given scope are segregated on
the homonym chain, and this was no longer the case for equality operators
in the specific case at stake.

gcc/ada/

	* sem_ch7.adb (Inspect_Untagged_Record_Completion): Also move the
	equality operator on the homonym chain if there is another equality
	operator in the private part.