ada: Flag renaming-as-spec as a body to inline

ada: Flag renaming-as-spec as a body to inline

For GNAT the frontend is only inlining subprograms with explicit specs,
including specs completed with renaming-as-body. For GNATprove the
frontend must also inline renamings acting as specs. Otherwise, we will
try to build a body-to-inline with code that is can't handle unusual
subprogram renamings, e.g. those of the form "object.call".

gcc/ada/

	* freeze.adb (Build_Renamed_Body): Rewrite subprogram renaming to
	subprogram declaration early and then set the Body_To_Inling flag.