Merge "Implement "fw" extension support for WeekFields.of API" am: a0f22cb7bb am: cf727fb33e

Original change: https://android-review.googlesource.com/c/platform/libcore/+/2057628

Change-Id: I0d1ed518eba01c08842f751f6e8b810e0646f51a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>