tests/qemu-iotests: Fix some tests that use --image-opts for other protocols

Tests 263, 284 and detect-zeroes-registered-buf use qemu-io
with --image-opts so we have to enforce IMGOPTSSYNTAX=true here
to get $TEST_IMG in shape for other protocols than "file".

Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-ID: <20240315111108.153201-9-thuth@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
3 files changed