[Ada] Unnesting: always transform local Raise statements

[Ada] Unnesting: always transform local Raise statements

2018-05-30  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_ch11.adb (Replace_Raise_By_Goto): The transfomation is legal even
	if the local raise statement includes a string expression. This
	expression might be picked up by an outer handler or discarded, but
	plays no role in this transformation.

From-SVN: r260949