Remove webkit_layout_tests from the Android 'KitKat Phone Tester' bot

See discussion thread:
https://groups.google.com/a/chromium.org/d/topic/blink-dev/338WKwWPbPI/discussion

This test suite requires maintainance to continue running on newer
Android versions, but the value being derived from running the suite on
Android bots is low. We test android by emulating it in various ways on
other platforms, or via other means such as content_browsertests on
Android bots.

- The not_site_per_process_webkit_layout_tests step is an Android
emulation of layout tests run on other platforms.
- The virtual/android/ VirtualTestSuite is an Android emulation of
a few layout tests run on other platforms.

R=dpranke@chromium.org

Bug: 567947
Change-Id: Ie740f3d8ce122324036e0c01772b47aa6af69434
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1629049
Commit-Queue: danakj <danakj@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Cr-Commit-Position: refs/heads/master@{#663312}
3 files changed