Builtin continuation frames know their height now. This is prework
to allow UnwindAndFindHandler to reconstructor the stack pointer for
the ContinueToBuiltin trampoline.

Bug: v8:7584
Change-Id: If1361f5bbac130c284cd46c0d39cc81e2df613d3
Reviewed-on: https://chromium-review.googlesource.com/983633Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52322}