qemu_test: add unsafe caching

Since we will throw away the result immediately after the test, there is
no need for guest disk flushes to actually make it to host disk, so make
write caching unsafe to improve performance just like debos does.

Signed-off-by: Robie Basak <[email protected]>

Author: basak-qcom

ci/qemu_test.py

@@ -42,7 +42,7 @@ def vm():
                 "-M",
                 "virt",
                 "-drive",
-                f"if=none,file={qcow_path},format=qcow,id=disk1",
+                f"if=none,file={qcow_path},format=qcow,id=disk1,cache=unsafe",
                 "-device",
                 "virtio-scsi-pci,id=scsi1",
                 "-device",