Silence excessive build logs when enable_incremental_javac = true

Silence excessive build logs when enable_incremental_javac = true

BUG=542421
Committed: https://crrev.com/9c3d57b1459a4a1a441c31e6ecf221293c25ddea
Cr-Commit-Position: refs/heads/master@{#354014}

[agrieve, 2015-10-14 02:25:13]

agrieve@chromium.org changed reviewers:
+ newt@chromium.org

[agrieve, 2015-10-14 02:31:31]

On 2015/10/14 02:25:13, agrieve wrote:
> mailto:agrieve@chromium.org changed reviewers:
> + mailto:newt@chromium.org

Was always my intention to have no logs by default, but seems some slipped
through. This patch assumes that everything going to stdout is from JMake and
all compiler messages go to stderr. Tested this assumption with compiler errors
and warnings and seems to hold.

[newt (away), 2015-10-14 02:44:36]

lgtm. thanks!

[agrieve, 2015-10-14 02:48:39]

The CQ bit was checked by agrieve@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2015-10-14 02:49:05]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1401363004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1401363004/1

[commit-bot: I haz the power, 2015-10-14 04:25:05]

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

[commit-bot: I haz the power, 2015-10-14 04:25:06]

Dry run: This issue passed the CQ dry run.

[agrieve, 2015-10-14 13:33:49]

The CQ bit was checked by agrieve@chromium.org

[commit-bot: I haz the power, 2015-10-14 13:34:10]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1401363004/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1401363004/1

[commit-bot: I haz the power, 2015-10-14 13:40:05]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-10-14 13:40:48]

Patchset 1 (id:??) landed as
https://crrev.com/9c3d57b1459a4a1a441c31e6ecf221293c25ddea
Cr-Commit-Position: refs/heads/master@{#354014}