[Ada] Infinite loop with concatenation and aspect

[Ada] Infinite loop with concatenation and aspect

This patch fixes a bug where an array object initialized with a
concatenation, and that has an aspect_specification for Alignment,
causes the compiler goes into an infinite loop.

2019-09-19  Bob Duff  <duff@adacore.com>

gcc/ada/

	* exp_ch3.adb (Rewrite_As_Renaming): Return False if there are
	any aspect specifications, because otherwise Insert_Actions
	blows up.

gcc/testsuite/

	* gnat.dg/concat3.adb: New testcase.

From-SVN: r275934