In this part: find, findIndex, findLast, findLastIndex

Drive-by: add missing tests for A.p.fill + detaching.

Bug: v8:11111
Change-Id: I7583ccce16bf294cc5ab6adbb7ce1f019a11ad18
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3721315Reviewed-by: Shu-yu Guo <syg@chromium.org>
Auto-Submit: Marja Hölttä <marja@chromium.org>
Commit-Queue: Shu-yu Guo <syg@chromium.org>
Cr-Commit-Position: refs/heads/main@{#81366}