di-longlong64-sync-withhelpers.c: Add comments to checks for multiple messages reported for one line of source code.

	* gcc.target/arm/di-longlong64-sync-withhelpers.c: Add comments
	to checks for multiple messages reported for one line of source code.
	* gcc.target/arm/di-longlong64-sync-withldrexd.c: Likewise.

From-SVN: r188480