Component items in a record declaration might include pragmas, which
must be ignored when detecting components with default expressions.

More a code cleanup than a bugfix, as it only affects artificial corner
cases. Found while fixing missing legality checks for variant component
declarations.

gcc/ada/

	* sem_ch3.adb (Check_CPP_Type_Has_No_Defaults): Iterate with
	First_Non_Pragma and Next_Non_Pragma.
	* exp_dist.adb (Append_Record_Traversal): Likewise.