Make sure WebAssembly's js-api exposes the correct attributes: writable,
enumerable and configurable.

Bug: v8:8319
Change-Id: I427533159d7975a42c0c5cb1babdc8a61f8198b5
Reviewed-on: https://chromium-review.googlesource.com/c/1351002
Commit-Queue: Adam Klein <adamk@chromium.org>
Reviewed-by: Adam Klein <adamk@chromium.org>
Reviewed-by: Ben Smith <binji@chromium.org>
Reviewed-by: Deepti Gandluri <gdeepti@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58053}