GS Cache: trivial unit test change

Using assertEqual other than assertEquals since the later one has been
deprecated.

BUG=chromium:824580
TEST=Ran unit tests.

Change-Id: If0f24d6381e179866838b069f64e755db1bdcd8d
Reviewed-on: https://chromium-review.googlesource.com/1096410
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Congbin Guo <guocb@chromium.org>
Reviewed-by: Congbin Guo <guocb@chromium.org>
2 files changed