Add off-main-thread-worker-script-fetch/external/wpt/referrer-policy

Bug: 835717, 880027
Change-Id: I074ea4b911132477853bf95be70a36b7d62c4f79
Reviewed-on: https://chromium-review.googlesource.com/c/1330903Reviewed-by: Hiroki Nakagawa <nhiroki@chromium.org>
Commit-Queue: Hiroshige Hayashizaki <hiroshige@chromium.org>
Cr-Commit-Position: refs/heads/master@{#609534}

third_party/WebKit/LayoutTests/VirtualTestSuites

@@ -694,6 +694,11 @@
     "base": "external/wpt/workers",
     "args": ["--enable-blink-features=OffMainThreadWorkerScriptFetch"]
   },
+  {
+    "prefix": "off-main-thread-worker-script-fetch",
+    "base": "external/wpt/referrer-policy",
+    "args": ["--enable-blink-features=OffMainThreadWorkerScriptFetch"]
+  },
   {
     "prefix": "off-main-thread-worker-script-fetch",
     "base": "fast/workers",

third_party/WebKit/LayoutTests/virtual/off-main-thread-worker-script-fetch/external/wpt/referrer-policy/README.txt

+This directory is for testing off-the-main-thread top-level worker classic
+script loading. See https://crbug.com/835717.