This CL addresses a TODO left from implementing Wasm entry to fast C
calls in https://chromium-review.googlesource.com/c/v8/v8/+/3440694/
and avoids generating a branch in case it's not needed (either because
the embedder isn't providing an options object, which is the case
for Wasm, or because we're not generating overloads).

Bug: chromium:1052746
Change-Id: I7323f85801c034f0c47877ea15f677a53d3acea3
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3650923
Commit-Queue: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Tobias Tebbi <tebbi@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80897}