Fix codec memory leaks in nanobench

Fix codec memory leaks in nanobench

SubsetTranslateBench.cpp:
Unref the color table, so it gets deleted.

SkBitmapRegionDecoderInterface.cpp:
Delete the stream if it is not used.

BUG=skia:3418
Committed: https://skia.googlesource.com/skia/+/e361781bf7ce8acd4af00c426b34596804d45d77

[scroggo, 2015-10-09 19:02:35]

scroggo@google.com changed reviewers:
+ msarett@google.com

[scroggo, 2015-10-09 19:02:51]

The CQ bit was checked by scroggo@google.com to run a CQ dry run

[commit-bot: I haz the power, 2015-10-09 19:03:01]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1396113003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1396113003/1

[msarett, 2015-10-09 19:08:15]

LGTM

[commit-bot: I haz the power, 2015-10-09 19:09:52]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-10-09 19:09:53]

Dry run: This issue passed the CQ dry run.

[scroggo, 2015-10-09 19:15:02]

The CQ bit was checked by scroggo@google.com

[commit-bot: I haz the power, 2015-10-09 19:15:14]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1396113003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1396113003/1

[commit-bot: I haz the power, 2015-10-09 19:16:02]

Committed patchset #1 (id:1) as
https://skia.googlesource.com/skia/+/e361781bf7ce8acd4af00c426b34596804d45d77