ada: Compiler hangs on container aggregate with function call as key expression

ada: Compiler hangs on container aggregate with function call as key expression

The compiler hangs (or may crash, if assertions are enabled) when compiling
an iterated association of a container aggregate that has a key expression
given by a function call. The resolution of the call leads to a blowup in
Build_Call_Marker, because the temporary copy of the expression that's
analyzed has an Empty parent, causing insertion of the call marker to fail.
The fix for this is to preanalyze, rather than analyze, the copy of the key
expression (Build_Call_Marker will return without creating a call marker in
the case of preanalysis).

gcc/ada/

	* sem_aggr.adb (Resolve_Iterated_Association): Call
	Preanalyze_And_Resolve instead of Analyze_And_Resolve on a key
	expression of an iterated association.