[Ada] Spurious restriction violation on Ghost code

[Ada] Spurious restriction violation on Ghost code

2019-10-10  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_ch6.adb (Expand_Simple_Function_Return_Statement): If the
	function to which the return statement applies is an
	Ignored_Ghost_Function, do not indicate that it uses the
	secondary stack when the return type is unconstrained.

From-SVN: r276814