[Ada] Another case where freezing incorrectly suppresses checks

[Ada] Another case where freezing incorrectly suppresses checks

Avoid improperly suppressing checks for the wrapper subprogram that is
built when a null type extension inherits (and does not override) a
function with a controlling result. This is a follow-up to other changes
already made on this ticket.

gcc/ada/

	* exp_ch3.adb (Make_Controlling_Function_Wrappers): Set the
	Corresponding_Spec field of a wrapper subprogram body before
	analyzing the subprogram body; the field will be set (again)
	during analysis, but we need it to be set earlier.
	* exp_ch13.adb (Expand_N_Freeze_Entity): Add wrapper subprogram
	bodies to the list of declarations for which we do not want to
	suppress checks.