ada: Delay expansion of iterator specification in preanalysis

ada: Delay expansion of iterator specification in preanalysis

When preanalysing spec expression (e.g. expression of an expression
function), the name of iterator specification should not be expanded.

This patch simplifies a complicated condition for delaying expansion
within quantified expressions and iterated component associations.

gcc/ada/

	* sem_ch5.adb (Analyze_Iterator_Specification): Delay expansion
	based on Full_Analysis flag.