This is non-standard and not even documented on MDN.

On Firefox, setting RegExp.multiline to true adds the multiline flag to all
newly created RegExp objects (both from constructor and from literal).

In V8 this has no effect.

Source archaelogy shows that this is from the initial commit.

R=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/1410993008

Cr-Commit-Position: refs/heads/master@{#31673}