Note: by the time the old code used to call `getBaseLevelInternalFormat`, the base level image has already been updated with `redefine()` call above, thus the check `internalformat != storageFormat` wasn't correct.

Change-Id: I3da6df54490d6e72e5094388ed7e39a4c7d920d2
Reviewed-on: https://chromium-review.googlesource.com/862256Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Dzmitry Malyshau <dmalyshau@mozilla.com>
Commit-Queue: Geoff Lang <geofflang@chromium.org>