Embedded builtins have been regressing benchmarks incrementally as
more and more builtins were moved to the embedded blob. This has made
recognition and analysis of other possible performance issues more
difficult.

Let's disable embedded builtins until their performance is at an
acceptable level.

Bug: v8:6666
Change-Id: I21a1274f3d5a65063127b0a8604df6dd0d3c0c95
Reviewed-on: https://chromium-review.googlesource.com/1049550
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#53062}