Remove obsolete timeline-layout test

This test is covered by an inspector-protocol test [1], so we do not
need this as well as it provides no extra coverage.

[1]: https://source.chromium.org/chromium/chromium/src/+/main:third_party/blink/web_tests/inspector-protocol/timeline/timeline-layout.js

Bug: 1444416
Change-Id: Ifed9a25bb4d27f123fb4550a4d1f643c18366186
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4548238


Reviewed-by: Mathias Bynens <mathias@chromium.org>
Commit-Queue: Mathias Bynens <mathias@chromium.org>
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1146412}