[Ada] Crash on a Storage_Size aspect depending on attr. of another type

[Ada] Crash on a Storage_Size aspect depending on attr. of another type

This patch fixes a crash on an aspect specification for Storage_Size for
a type T when the expression for the aspect depends on attributes of a
previously declared type that is not frozen yet. The  temporary
declaration that captures the value of the aspect must be part of the
actions attached to the freeze node for T.

2019-08-20  Ed Schonberg  <schonberg@adacore.com>

gcc/ada/

	* exp_ch13.adb (Expand_N_Attribute_Definition_Clause, case
	Storage_Size): If the expression for Storage_Size is not static
	it may depend on characterstics of another type that may bot be
	frozen yet, so the elaboration of the expression for the aspect
	must be attached directly to the freeze actions of the type to
	which it applies.

gcc/testsuite/

	* gnat.dg/storage_size1.adb: New testcase.

From-SVN: r274742