s390: Add test case for disassembler option warn-areg-zero

gas/
	* testsuite/gas/s390/s390.exp: Add test cases for s390-specific
	assembler option "warn-areg-zero".
	* testsuite/gas/s390/zarch-warn-areg-zero.s: Likewise.
	* testsuite/gas/s390/zarch-warn-areg-zero.l: Likewise.

Reviewed-by: Andreas Krebbel <krebbel@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
3 files changed