qemu-iotests: add cloop input validation tests

qemu-iotests: add cloop input validation tests

Add a cloop format-specific test case.  Later patches add tests for
input validation to the script.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
(cherry picked from commit 05560fcebb1528f4354f6f24d1eb8cdbcdf2c4b2)

Conflicts:
	tests/qemu-iotests/group

*fixed context mismatches in group file

Signed-off-by: Michael Roth <mdroth@linux.vnet.ibm.com>