Remove W3CImportExpectations that were added due to test failures.

These were probably the result of getting bad expectations during a WPT
import, and were put in W3CImportExpectations by the sheriff.  This
isn't really what W3CImportExpectations is for; it's much more like
NeverFixTests, saying that a test is something we don't want to
implement (but even stronger, since they don't end up in our
repository).

This removes the entries in the hope that the expectations will be
generated correctly on the next import.

Fixed: 1250215
Change-Id: I5a8bb54bc4f1e19e1c3535b4062b1273e5f37c68
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3866333


Reviewed-by: Weizhong Xia <weizhong@google.com>
Commit-Queue: David Baron <dbaron@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1041132}