Convert mojo_public_system_unittests to run exclusively on Swarming

Convert mojo_public_system_unittests to run exclusively on Swarming

0 configs already ran on Swarming
20 used to run locally and were converted:
- chromium.fyi.json: ClangToTLinux tester
- chromium.fyi.json: ClangToTMac tester
- chromium.fyi.json: ClangToTMacASan tester
- chromium.fyi.json: Linux Trusty
- chromium.fyi.json: Linux Trusty (dbg)
- chromium.linux.json: Android GN
- chromium.linux.json: Linux Tests
- chromium.linux.json: Linux Tests (dbg)(1)
- chromium.linux.json: Linux Tests (dbg)(1)(32)
- chromium.mac.json: Mac10.10 Tests
- chromium.mac.json: Mac10.6 Tests
- chromium.mac.json: Mac10.8 Tests
- chromium.mac.json: Mac10.9 Tests
- chromium.mac.json: Mac10.9 Tests (dbg)
- chromium.memory.fyi.json: Linux ChromeOS MSan Tests
- chromium.memory.fyi.json: Linux MSan Tests
- chromium.win.json: Vista Tests (1)
- chromium.win.json: Win 7 Tests x64 (1)
- chromium.win.json: Win7 Tests (1)
- chromium.win.json: Win7 Tests (dbg)(1)

Ran:
  ./manage.py --convert mojo_public_system_unittests

R=jam@chromium.org
BUG=98637
Committed: https://crrev.com/b3a74ebef45222ef06ec7003d9e947c1314dda37
Cr-Commit-Position: refs/heads/master@{#346327}

[M-A Ruel, 2015-07-17 22:39:36]

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

[commit-bot: I haz the power, 2015-07-17 22:40:50]

Dry run: CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1230823008/1

[commit-bot: I haz the power, 2015-07-18 01:30:31]

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

[commit-bot: I haz the power, 2015-07-18 01:30:32]

Dry run: This issue passed the CQ dry run.

[M-A Ruel, 2015-07-20 16:44:23]

It's this one that you wanted to lgtm. :)

[jam, 2015-07-20 16:45:01]

lgtm

[M-A Ruel, 2015-08-30 23:38:46]

The CQ bit was checked by maruel@chromium.org

[commit-bot: I haz the power, 2015-08-30 23:38:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1230823008/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1230823008/1

[commit-bot: I haz the power, 2015-08-31 01:47:08]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-31 01:47:40]

Patchset 1 (id:??) landed as
https://crrev.com/b3a74ebef45222ef06ec7003d9e947c1314dda37
Cr-Commit-Position: refs/heads/master@{#346327}