Reland of Move side-loaded test data /sdcard -> /sdcard/chromium_tests_root

Reason for reland:
Updated webview tests that broke (WebViewLayoutTest.java)

And use delete_device_stale=True when pushing. This will prevent tests
mistakenly passing when they depend on stale data files from a previous test.

TBR=jbudorick@chromium.org,thakis@chromium.org,mef@chromium.org
BUG=607169

Review-Url: https://codereview.chromium.org/2018663002
Cr-Commit-Position: refs/heads/master@{#396479}
26 files changed