Fix WebView tests failures running with the BackForwardCache

The CL adds the following patches to fix the failing tests when running
with the BackForwardCache.

* Export the WebViewBackForwardCache feature to java.
* Fix AwPrerenderTest.testAwContentsIoThreadClientHandleFrameTreeSwapBack to
  verify the behavior when BFCache is enabled.
* Replace pageFinishedHelper with a custom signal from javascript in
  NavigationHistoryTest when BFCache is enabled.
* Skip the check for PAGE_DELETED in the NavigationListenerTest if
  the page is stored into the BFCache.

Bug: 331587668
Change-Id: Ie1888ef2f233fa31adbfb017caabb6c73a787061
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5553239


Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Commit-Queue: Jiacheng Guo <gjc@google.com>
Reviewed-by: Richard (Torne) Coles <torne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1313146}