Re-enable fast/canvas/canvas-composite-video tests on Linux

These tests got disabled in https://crrev.com/c/3202119.
It seems that the rebaseline-cl tool wasn't producing baselines for
the linux_layout_tests_layout_ng_disabled bot. This bot was removed in
https://crrev.com/c/4159905 and https://crrev.com/c/4152833. Thus, we
can now re-enable these tests as they seem to be passing on all
platforms.

While these tests were disabled for Linux, other platforms got
re-baselines to account for code updates (in https://crrev.com/c/3817461
and https://crrev.com/c/3823687). Because of the TestExpectation
entry, the Linux baseline wasn't updated along with the others. We must
therefore rebaseline the Linux baselines now.

Bug: 40190804
Change-Id: I8baf4f8cf1b41b78223d9c8b16cc72b667bf7805
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5805133
Reviewed-by: Andres Ricardo Perez <andresrperez@chromium.org>
Commit-Queue: Jean-Philippe Gravel <jpgravel@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1347404}