[automerged blank] Re-enable UFFD GC for the February train, but with a different flag. 2p: a3c169dce0

Blank merge reason: Change-Id I163f808399eb27393e00dbb149d5941ff3db277f with SHA-1 60e0a00cbf is in history

Original change: https://googleplex-android-review.googlesource.com/c/platform/art/+/20665667


Change-Id: I3c8892494e3a43897efb8b4b3e5b1709735871a7
Merged-In: I163f808399eb27393e00dbb149d5941ff3db277f