When we get a buffer with vertex data in an unsupported format or
alignment, correct that as we copy it to a DynamicBuffer, then use
the copy.  Enable tests.

BUG=angleproject:2405

Change-Id: I2132abea4d936f6b53d9209be7f99a0e2d8de219
Reviewed-on: https://chromium-review.googlesource.com/1141277
Commit-Queue: Frank Henigman <fjhenigman@chromium.org>
Reviewed-by: Geoff Lang <geofflang@chromium.org>