Convert all layer WPT tests to synchronous testharness tests

This is a follow to https://crrev.com/c/5392305, where the new "sync"
test_type was added and one layer test was converted. This CL converts
all other layer tests, for consistency.

Bug: 330885075
Change-Id: Ibc36291891db0ee0ce18d5a6f98bbb064bf771a3
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5424822


Reviewed-by: Andres Ricardo Perez <andresrperez@chromium.org>
Commit-Queue: Jean-Philippe Gravel <jpgravel@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1283144}