SPARK RM 7.7(8) mandates that the freezing point of a tagged type must
occur within the so-called early call region of all its primitives.
This check may lead to spurious errors due to generated constructs being
considered in the search for the start of the early call region.

Tested on x86_64-pc-linux-gnu, committed on trunk

gcc/ada/

	* sem_elab.adb (Is_Suitable_Construct): Fix for generated
	constructs.