With the exception of the InterpreterEntryTrampoline, all builtins are
now isolate-independent and can be embedded into the binary.

This CL updates the corresponding list and also contains a few smallish
tweaks to support having these builtins off the heap:

* wasm: copy the off-heap builtin, not its trampoline.
* Code::contains: support off-heap builtins.
* JSFunction::is_compiled: compare builtin index instead of identity
  (this is relevant during mksnapshot when we transition from the
  on-heap builtin to its off-heap representation + the trampoline).
* Remove old DCHECKs.
* A few tweaks in macro-assembler ports that have snuck in recently.

Bug: v8:6666
Change-Id: Iabf5b47ade3826a4da35b6b75a4e61614f0158b0
Reviewed-on: https://chromium-review.googlesource.com/1032777
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Michael Starzinger <mstarzinger@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52935}