{FrameArray} needs a way to keep {WasmCode} alive from a JS container.
This CL instruces {GlobalWasmCodeRef}, which is the equivalent to a
global handle: It increments the {WasmCode} reference counter on
construction and decrements it on destruction.
The {GlobalWasmCodeRef} is held in a {Managed} from JS.

R=titzer@chromium.org

Bug: v8:8217
Change-Id: I5604a666840c27078db63c8618412ca412525be1
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1533862
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Reviewed-by: Ben Titzer <titzer@chromium.org>
Cr-Commit-Position: refs/heads/master@{#60441}