The current libwebm integration test samples contain `libwebm-0.2.1`
however we have updated to a newer version of libwebm so we need to
update the samples.
As of `libwebm-0.3.0` this signature has been frozen so we won't have to
do this again.
This changes almost all encrypted tests to use DiffDir. The remaining
un-updated tests are tests that won't match every time.
Change-Id: I858bbaa0beea34887cc3100eb784aa2aecd5a0a5