Test for boot cache device mapper

Test verifies build boot cache and verifies the resulting block map.
Test corrupts the block map and verifies it still works.

BUG=chromium-os:25441
TEST=ran on stumpy

Change-Id: Id6ecaaf57a0e3da0af140ce419a5f5dd83cb3156
Reviewed-on: https://gerrit.chromium.org/gerrit/35464
Reviewed-by: Paul Taysom <taysom@chromium.org>
Tested-by: Paul Taysom <taysom@chromium.org>
Reviewed-by: Mandeep Singh Baines <msb@chromium.org>
Commit-Ready: Paul Taysom <taysom@chromium.org>
2 files changed