[Ada] Crash on expression functions within quantified expressions

[Ada] Crash on expression functions within quantified expressions

This patch fixes an issue whereby using a call to an expression function
as the domain of iteration for a loop would trigger a crash due to the
function not being frozen appropriately.

2018-09-26  Justin Squirek  <squirek@adacore.com>

gcc/ada/

	* sem_ch5.adb (Analyze_Iterator_Specification): Add conditional
	to freeze called functions within iterator specifications during
	full analysis.
	(Preanalyze_Range): Minor typo fix.

gcc/testsuite/

	* gnat.dg/expr_func8.adb: New testcase.

From-SVN: r264612