Revert "Update platform_CrosDisksFilesystem ext2/3/4 tests."

This reverts commit dc6e31a09ca866b75bd06caa6323828b6f6ec5f0.

CL:223391 re-enables the support of ext2/3/4 filesystem in cros-disks.
This CL updates platform_CrosDisksFilesystem ext2/3/4 tests to verify
that mounting of ext2/3/4 filesystems via cros-disks succeeds again.

BUG=chromium:315401
TEST=Run platform_CrosDisksFilesystem tests.

(cherry picked from commit 4fdcff4414f3625bbc1ee7bd3a88446fc45196f0)

Change-Id: Id812a197d2efea3799d50a93c5065696de23699f
Reviewed-on: https://chromium-review.googlesource.com/223421
Reviewed-by: Ben Chan <benchan@chromium.org>
Commit-Queue: Ben Chan <benchan@chromium.org>
Tested-by: Ben Chan <benchan@chromium.org>
4 files changed