Version 4.3.61.33 (cherry-pick)

Merged 47421760

Map::ReconfigureProperty() should mark map as unstable when it returns a different map.

BUG=chromium:502930
LOG=N
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/1213123003.

Cr-Commit-Position: refs/branch-heads/4.3@{#38}
Cr-Branched-From: f5c0a23a-refs/heads/4.3.61@{#1}
Cr-Branched-From: 0a7d4f49-refs/heads/master@{#27508}