Revert of Pass --images '' to nanobench to disable image benchmarking. (patchset #1 id:1 of https://codereview.chromium.org/1381703003/ )

Reason for revert:
I have attempted to fix the problems that caused running nanobench with images to fail, so testing to see if they are in fact fixed.

Original issue's description:
> Pass --images '' to nanobench to disable image benchmarking.
>
> Enabling image benchmarking has caused most nanobench runs to fail,
> both Debug and Release.
>
> BUG=skia:3418
> NOTREECHECKS=true
> TBR=scroggo@google.com
>
> Committed: https://skia.googlesource.com/skia/+/1f7039c6c5f0f118b629994b0bac255345e5abd6

BUG=skia:3418

Review URL: https://codereview.chromium.org/1400633002
2 files changed