This CL removes the V8_EMBEDDED_BUILTINS define,
FLAG_embedded_builtins, and all code for supporting
non-embedded-builtin builds.

Bug: v8:6666,v8:8519
Change-Id: I2ad7bd6614c7cd404b83d3d2bf5ff91d7b55ff2a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1866569
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64461}