Fix generate-test-wbns.sh used in WPT

It looks generate-test-wbns.sh fails with two errors:

1. nested/resource.js is missing
2. cors/resource.json is wrong. It should be cors/resource.cors.json

BUG=1082020

Change-Id: I18a87f59784d6c36e050a64567c1ba671af0468a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2627209Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
Reviewed-by: Tsuyoshi Horo <horo@chromium.org>
Commit-Queue: Hayato Ito <hayato@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842933}

third_party/blink/web_tests/external/wpt/web-bundle/resources/generate-test-wbns.sh

@@ -74,5 +74,5 @@ gen-bundle \
 gen-bundle \
   -version b1 \
   -har cross-origin.har \
-  -primaryURL $wpt_test_https_origin/web-bundle/resources/wbn/cors/resource.json \
+  -primaryURL $wpt_test_https_origin/web-bundle/resources/wbn/cors/resource.cors.json \
   -o wbn/cors/cross-origin.wbn