Swap bits between bitfield2 and bitfield3 so that bitfield2 doesn't change
across named property transitions. This will allow us to share bf1/bf2 through
the descriptor array.

Change-Id: I3579ae89189ae0729cd492db1afb29cf90981f6a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1657908Reviewed-by: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Toon Verwaest <verwaest@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62134}