Upgrade jimfs to v1.2. am: 047cfe3604

Original change: https://android-review.googlesource.com/c/platform/external/jimfs/+/2283353

Change-Id: I5e9568a0cab4ee891e40d85d8b91f78688df5b12
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>