Increase number of interactive_ui_tests shards 1 -> 3 on chromium.memory

Increase number of interactive_ui_tests shards 1 -> 3 on chromium.memory

This should reduce cycle time difference between linux_chromium_asan_rel
and linux_chromium_asan_rel_ng .

BUG=387743
Committed: https://crrev.com/2be6ee49311e3880fceeea9f5ee3ebae61d8b03f
Cr-Commit-Position: refs/heads/master@{#327027}

[Paweł Hajdan Jr., 2015-04-27 08:45:58]

phajdan.jr@chromium.org changed reviewers:
+ sergiyb@chromium.org

[Sergiy Byelozyorov, 2015-04-27 09:28:55]

lgtm

[Paweł Hajdan Jr., 2015-04-27 10:27:07]

The CQ bit was checked by phajdan.jr@chromium.org

[commit-bot: I haz the power, 2015-04-27 10:27:11]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1104983002/1

[commit-bot: I haz the power, 2015-04-27 11:37:00]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-27 11:38:07]

Patchset 1 (id:??) landed as
https://crrev.com/2be6ee49311e3880fceeea9f5ee3ebae61d8b03f
Cr-Commit-Position: refs/heads/master@{#327027}