Revert "Make ResourcePrefetchPredictor use correct NetworkIsolationKeys."

This reverts commit 3ce9f4d83a6370cdee315f5a30dfd66142c64698.

Reason for revert: Broke browser_tests on win-asan bot.

https://ci.chromium.org/p/chromium/builders/ci/win-asan/6832

Original change's description:
> Make ResourcePrefetchPredictor use correct NetworkIsolationKeys.
> 
> ResourcePrefetchPredictor was always using the origin of the initial
> page being navigated to in constructing the NetworkIsolationKey.
> With this CL, it uses the origin it expects the page to redirect to
> instead.
> 
> Bug: 987735
> Change-Id: Ic66c33bb5f99a9a00485ffe46c70e0947e0e430b
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1730782
> Reviewed-by: Tarun Bansal <tbansal@chromium.org>
> Reviewed-by: Egor Pasko <pasko@chromium.org>
> Commit-Queue: Matt Menke <mmenke@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#685173}

TBR=pasko@chromium.org,mmenke@chromium.org,tbansal@chromium.org

Change-Id: I7af5589722eafc8a0157c639acb357e8d28ae0bf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 987735
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1744512
Reviewed-by: Scott Little <sclittle@chromium.org>
Commit-Queue: Scott Little <sclittle@chromium.org>
Cr-Commit-Position: refs/heads/master@{#685241}
6 files changed