This CL does two things:

1. It introduces Call/JumpCodeObject as the bottleneck for all calls
   to non-heap-constant Code objects; and
2. it dispatches directly to the off-heap entry point for all embedded
   code.

Codegen at runtime remains unchanged to preserve the shorter,
branch-less calling sequence.

Bug: v8:7777
Change-Id: I15fdcb51625209904c6a56737f085a23219319b9
Reviewed-on: https://chromium-review.googlesource.com/c/1382461
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Reviewed-by: Sigurd Schneider <sigurds@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58440}