[Cleanup] Remove Screenshot measurement test from telemetry

[Cleanup] Remove Screenshot measurement test from telemetry.

As Screenshot measurement is no longer used, remove it from the telemetry tests.
The patch is based on the discussion in the graphics-dev [1] and the bug as well.

[1] https://groups.google.com/a/chromium.org/forum/#!topic/graphics-dev/R68sq4vjUwA

BUG=386572
R=nduca,ernstm

Committed: https://crrev.com/9070a8059b513108b09d30f96576b5ce11d0857a
Cr-Commit-Position: refs/heads/master@{#313233}

[RaviKasibhatla, 2015-01-23 13:50:30]

kphanee@chromium.org changed reviewers:
+ ernstm@chromium.org, nduca@chromium.org

[RaviKasibhatla, 2015-01-23 13:51:15]

kphanee@chromium.org changed reviewers:
+ kphanee@chromium.org

[RaviKasibhatla, 2015-01-23 13:51:16]

PTAL!

[ernstm, 2015-01-23 17:43:50]

On 2015/01/23 13:51:16, RaviKasibhatla wrote:
> PTAL!

LGTM

[r.kasibhatla, 2015-01-27 04:23:51]

The CQ bit was checked by r.kasibhatla@samsung.com

[commit-bot: I haz the power, 2015-01-27 04:24:43]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/869163003/1

[commit-bot: I haz the power, 2015-01-27 05:21:28]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-01-27 05:22:09]

Patchset 1 (id:??) landed as
https://crrev.com/9070a8059b513108b09d30f96576b5ce11d0857a
Cr-Commit-Position: refs/heads/master@{#313233}