Factory::NewFunction now requires names passed into it to be flat.
Make sure to flatten Wasm function names when creating new Wasm JS
functions.

Fixes: chromium:1047368
Change-Id: I7bd2d8bc83ae8fab901ab469872bce0f703fc3ec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2030738
Commit-Queue: Leszek Swirski <leszeks@chromium.org>
Auto-Submit: Leszek Swirski <leszeks@chromium.org>
Reviewed-by: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#66064}