Include WPT exp'ions file in BUILD targets

Bug: 937369
Change-Id: Icc5fa60040bad133567598cee73e549742e0dd83
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1744661
Auto-Submit: Luke Z <lpz@chromium.org>
Commit-Queue: Robert Ma <robertma@chromium.org>
Reviewed-by: Robert Ma <robertma@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685351}

third_party/blink/tools/BUILD.gn

@@ -29,6 +29,7 @@ action("build_wpt_metadata") {
     "//third_party/blink/web_tests/StaleTestExpectations",
     "//third_party/blink/web_tests/TestExpectations",
     "//third_party/blink/web_tests/VirtualTestSuites",
+    "//third_party/blink/web_tests/WPTOverrideExpectations",
   ]
 }
 
@@ -62,5 +63,6 @@ group("wpt_tests_isolate") {
     "//third_party/blink/web_tests/StaleTestExpectations",
     "//third_party/blink/web_tests/TestExpectations",
     "//third_party/blink/web_tests/VirtualTestSuites",
+    "//third_party/blink/web_tests/WPTOverrideExpectations",
   ]
 }