Import wpt@421cc5ec61be5d407336a446b4da473c889ce518

Using wpt-import in Chromium d401a1af.

Note to sheriffs: This CL imports external tests and adds
expectations for those tests; if this CL is large and causes
a few new failures, please fix the failures by adding new
lines to TestExpectations rather than reverting. See:
https://chromium.googlesource.com/chromium/src/+/master/docs/testing/web_platform_tests.md

NOAUTOREVERT=true
TBR=foolip@google.com

No-Export: true
Change-Id: Ie0daca1a865411148df0a266e615fe99031b24f7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2305969Reviewed-by: WPT Autoroller <wpt-autoroller@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: WPT Autoroller <wpt-autoroller@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#789758}

third_party/blink/web_tests/NeverFixTests

@@ -2147,4 +2147,4 @@ virtual/subresource-web-bundles/external/wpt/web-bundle/subresource-loading/* [
 external/wpt/native-file-system/showSaveFilePicker-manual.https.html [ Skip ]
 
 # This test requires a physical device connected.
-wpt_internal/serial/serialPort_loopback-manual.https.html [ Skip ]
+wpt_internal/serial/serialPort_loopback-manual.https.html [ Skip ]
\ No newline at end of file