Add cross-origin-embedder-policy to the virtual test configuration

This CL adds external/wpt/html/cross-origin-embedder-policy/ tests
to the PlzDedicatedWorker virtual test configuration and the "Tests"
section in core/workers/README.md.

Bug: 1060837
Change-Id: I2f2e654710ecba794e4c4e3c4e03138db23fd1f1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2628271
Commit-Queue: Asami Doi <asamidoi@chromium.org>
Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Cr-Commit-Position: refs/heads/master@{#843969}

third_party/blink/renderer/core/workers/README.md

@@ -160,6 +160,7 @@ in the following files and directories to avoid breakage.
 
 - Web Platform Tests
   - [content-security-policy/](https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/content-security-policy/)
+  - [cross-origin-embedder-policy/](https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/html/cross-origin-embedder-policy/)
   - [fetch/](https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/fetch/)
   - [mixed-content/](https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/mixed-content/)
   - [performance-timeline/](https://cs.chromium.org/chromium/src/third_party/blink/web_tests/external/wpt/performance-timeline/)

third_party/blink/web_tests/TestExpectations

@@ -5877,3 +5877,5 @@ crbug.com/1164459 [ Mac10.15 ] external/wpt/preload/download-resources.html [ Pa
 
 # CSS spelling and grammar features (issue 1163437)
 crbug.com/1147859 external/wpt/css/css-pseudo/highlight-painting-order.html [ Failure ]
+
+crbug.com/1060837 virtual/plz-dedicated-worker/external/wpt/html/cross-origin-embedder-policy/dedicated-worker.https.html [ Timeout ]

third_party/blink/web_tests/VirtualTestSuites

@@ -436,6 +436,7 @@
               "external/wpt/content-security-policy/worker-src",
               "external/wpt/fetch/",
               "external/wpt/html/browsers/offline/appcache/workers/",
+              "external/wpt/html/cross-origin-embedder-policy",
               "external/wpt/referrer-policy",
               "external/wpt/resource-timing",
               "external/wpt/service-workers",

third_party/blink/web_tests/virtual/plz-dedicated-worker/external/wpt/html/cross-origin-embedder-policy/dedicated-worker-cache-storage.https-expected.txt

+This is a testharness.js-based test.
+PASS coep-none coep-none corp-cross-origin
+PASS coep-none coep-none corp-undefined
+PASS coep-none coep-require-corp corp-cross-origin
+FAIL coep-none coep-require-corp corp-undefined assert_equals: expected "failure" but got "success"
+FAIL coep-require-corp coep-none corp-cross-origin assert_equals: expected "error" but got "success"
+FAIL coep-require-corp coep-none corp-undefined assert_equals: expected "error" but got "failure"
+PASS coep-require-corp coep-require-corp corp-cross-origin
+PASS coep-require-corp coep-require-corp corp-undefined
+Harness: the test ran to completion.
+