Remove Duplicate LayerTreeHostCommonTest on Main Thread

Remove Duplicate LayerTreeHostCommonTest on Main Thread

Remove these two tests because there are compositor thread version of
them that does the exact same thing. These tests are used to test for
RenderSurfaceLayerList generation, which we are looking to only do on
compositor thread.

This deletes:
    LayerTreeHostCommonTest.SubtreeHidden_SingleLayer
    LayerTreeHostCommonTest.SubtreeHidden_TwoLayers

BUG=502041, 504466
R=enne
CQ_INCLUDE_TRYBOTS=tryserver.blink:linux_blink_rel

Committed: https://crrev.com/6172036d2c7275b949346e051d4cafad9f1b3e21
Cr-Commit-Position: refs/heads/master@{#340184}

[enne (OOO), 2015-07-23 22:15:14]

The CQ bit was checked by enne@chromium.org

[enne (OOO), 2015-07-23 22:15:15]

lgtm

[commit-bot: I haz the power, 2015-07-23 22:16:04]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1257443003/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1257443003/1

[commit-bot: I haz the power, 2015-07-23 22:21:38]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-23 22:22:16]

Patchset 1 (id:??) landed as
https://crrev.com/6172036d2c7275b949346e051d4cafad9f1b3e21
Cr-Commit-Position: refs/heads/master@{#340184}