This makes function objects constructed via the {WebAssembly.Function}
constructor callable directly from JavaScript (not just from within
WebAssembly modules). Semantics are as if the function performed the
transition JS-to-Wasm and then Wasm-to-JS in sequence.

R=clemensh@chromium.org
TEST=mjsunit/wasm/type-reflection
BUG=v8:7742

Change-Id: Ic7dcf36ccfda1b473f2541e49419f4d2ee38bc2c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1720809
Commit-Queue: Michael Starzinger <mstarzinger@chromium.org>
Reviewed-by: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62953}