Update mirror layer tests to support detach mirror flag

We changed mirroring behavior to ignore the local transforms
to support cases like mirroring a freeform window.
This cl fixes the tests to update the position of the mirrored
layer if the flag is set.

Bug: 337845753
Test: presubmit

Change-Id: I28294c36afb4d9f0de2e6c6017332617315f0c4d