Function name property is now standardized in ES6. It was a Mozilla proprietary
extension before. With ES6, the property was made configurable, so that it can
be used instead of another proprietary property, displayName.

This is a revert of revert https://chromium.googlesource.com/v8/v8.git/+/c791d8411225aa95518c880defd9a5b1ea243afc.

Last time this broke a Chrome browser test which has since been updated:

https://chromium.googlesource.com/chromium/src/+/5f75a3be4c9334aba627d6c5eb884adf965e1d78

BUG=v8:3333
LOG=N
R=mstarzinger@chromium.org,verwaest@chromium.org
CQ_INCLUDE_TRYBOTS=tryserver.chromium.linux:linux_chromium_rel_ng;tryserver.blink:linux_blink_rel

Review URL: https://codereview.chromium.org/977003004

Cr-Commit-Position: refs/heads/master@{#26996}