testsuite: Fix hwasan/arguments-3.c failures

testsuite: Fix hwasan/arguments-3.c failures

This testcase had three dg-error tests for ".*<message>.*".
But since . matches \n in Tcl regexps, the first dg-error
ate all the output, leaving the other two to fail.

The regexp is eventually embedded in a larger one, so we
can't prefix it with (?n).  But the .*s aren't necessary,
since dg-error tests for a partial rather than a full match.

gcc/testsuite/
	* c-c++-common/hwasan/arguments-3.c: Remove extraneous .*s.