Revert "CORS check for prefetched subresource signed exchanges"

This reverts commit 73e22231412bef575cfa5dcbf64dd7e6a35c99e9.

Reason for revert:

Findit (https://goo.gl/kROfz5) identified CL at revision 662114 as the
culprit for flakes in the build cycles as shown on:
https://analysis.chromium.org/p/chromium/flake-portal/analysis/culprit?key=ag9zfmZpbmRpdC1mb3ItbWVyQwsSDEZsYWtlQ3VscHJpdCIxY2hyb21pdW0vNzNlMjIyMzE0MTJiZWY1NzVjZmE1ZGNiZjY0ZGQ3ZTZhMzVjOTllOQw

Sample Failed Build: https://ci.chromium.org/buildbot/chromium.memory/Linux%20TSan%20Tests/38797

Sample Failed Step: content_browsertests on Ubuntu-16.04

Sample Flaky Test: SignedExchangeSubresourcePrefetchBrowserTest/SignedExchangeSubresourcePrefetchBrowserTest.CORS/0

Original change's description:
> CORS check for prefetched subresource signed exchanges
> 
> Bug: 935267
> Change-Id: I453bec48331cdbc203f96ccd3c99168f2f1734d4
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1616937
> Commit-Queue: Tsuyoshi Horo <horo@chromium.org>
> Reviewed-by: Kinuko Yasuda <kinuko@chromium.org>
> Reviewed-by: Takashi Toyoshima <toyoshim@chromium.org>
> Reviewed-by: Kunihiko Sakamoto <ksakamoto@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#662114}


Change-Id: I6ab6df81f0dd0e136e2e07f154f3ac9f26712ae3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 935267
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1624588
Cr-Commit-Position: refs/heads/master@{#662140}
5 files changed