[Ada] Static expression function problems with -gnatc and -gnatd.F (SPARK mode)

[Ada] Static expression function problems with -gnatc and -gnatd.F (SPARK mode)

gcc/ada/

	* exp_ch6.adb (Expand_Simple_Function_Return): Remove ugly code
	that was copying the return expression, resetting Analyzed
	flags, etc. for the return expression of static expression
	functions.
	* inline.adb (Inline_Static_Expression_Function_Call): Set the
	Parent of the copied expression to that of the call. This avoids
	a blowup in Insert_Actions when GNATprove_Mode is set and there
	are nested SEF calls. Add ??? comment.
	* sem_ch6.adb (Analyze_Expression_Function): In the case of a
	static expression function, create a new copy of the expression
	and replace the function's expression with the copy; the
	original expression is used in the expression function's body
	and will be analyzed and rewritten, and we need to save a clean
	copy for later use in processing static calls to the function.
	This allows removing the kludgy code that was in
	Expand_Simple_Function_Return.
	* sem_eval.adb (Eval_Qualified_Expression): Return immediately
	if any errors have been posted on the qualified expression, to
	avoid blowups when GNATprove_Mode is enabled (or with -gnatd.F),
	since illegal static expressions are handled differently in that
	case and attempting to fold such expressions would fail.