Fix a bug that LauncherActivityTest never executes any tests

Fix a bug that LauncherActivityTest never execute any tests

Android test annotation is missing in the only one test in this file.
This CL fixes it.

BUG=NONE

Committed: https://crrev.com/100d94803efc087b0f9dd05c69792e4bdc2ffe5c
Cr-Commit-Position: refs/heads/master@{#333149}

[Ian Wen, 2015-06-05 21:35:06]

ianwen@chromium.org changed reviewers:
+ mariakhomenko@chromium.org

[Maria, 2015-06-05 21:36:45]

lgtm

[Ian Wen, 2015-06-05 21:38:59]

The CQ bit was checked by ianwen@chromium.org

[commit-bot: I haz the power, 2015-06-05 21:40:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1165513006/1

[commit-bot: I haz the power, 2015-06-05 22:06:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-05 22:07:00]

Patchset 1 (id:??) landed as
https://crrev.com/100d94803efc087b0f9dd05c69792e4bdc2ffe5c
Cr-Commit-Position: refs/heads/master@{#333149}