This patch corrects the mechanism which ensures that a package with a null
Abstract_State does not introduce hidden state, by ignoring internal states
and variables because they do not represent the "source" hidden state.

2018-07-16  Hristian Kirtchev  <kirtchev@adacore.com>

gcc/ada/

	* sem_util.adb (Check_No_Hidden_State): Ignore internally-generated
	states and variables.

gcc/testsuite/

	* gnat.dg/abstract_state1.adb, gnat.dg/abstract_state1.ads: New
	testcase.

From-SVN: r262722