Remove obsolete tracing layout tests

All these tests are covered by unit tests in devtools-frontend that test
the model (both the OPP model and the new TraceEngine model) and cover
all the parsing cases covered by these tests. Therefore, we do not need
to additionally maintain these tests.

Bug: 1444416
Change-Id: I1f4c439e3b55a4ad2f3575724ac25d7a0e4b307d
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4572817
Commit-Queue: Paul Irish <paulirish@chromium.org>
Commit-Queue: Jack Franklin <jacktfranklin@chromium.org>
Reviewed-by: Paul Irish <paulirish@chromium.org>
Auto-Submit: Jack Franklin <jacktfranklin@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1150665}