Revert of Use sched_yield on all POSIX platforms in PlatformThread.

Revert of Use sched_yield on all POSIX platforms in PlatformThread. (patchset #1 id:1 of https://codereview.webrtc.org/2716683002/ )

Reason for revert:
Reverting this change since it didn't affect the perf regressions we were seeing and actually seems to have caused more regressions as per comment in the bug.

Original issue's description:
> Use sched_yield on all POSIX platforms in PlatformThread.
> (not only MacOS)
> 
> This is a test to see if perf regressions we're seeing may be related to the use of nanosleep().
> 
> BUG=695438
> TBR=solenberg@webrtc.org
> 
> Review-Url: https://codereview.webrtc.org/2716683002 .
> Cr-Commit-Position: refs/heads/master@{#16807}
> Committed: https://chromium.googlesource.com/external/webrtc/+/384498abb5a0dc3e871e437e56b4a556c3ec1023

TBR=solenberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=695438
Review-Url: https://codereview.webrtc.org/2712133003
Cr-Commit-Position: refs/heads/master@{#16833}
Committed: https://chromium.googlesource.com/external/webrtc/+/3ba1a8cd1b875dc7bfcb7075fe4f78d0dfe0ff98

[tommi, 2017-02-24 17:12:18]

The CQ bit was checked by tommi@webrtc.org

[tommi, 2017-02-24 17:12:18]

Created Revert of Use sched_yield on all POSIX platforms in PlatformThread.

[commit-bot: I haz the power, 2017-02-24 17:12:27]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.webrtc.org/...

[commit-bot: I haz the power, 2017-02-24 17:12:33]

CQ is committing da patch.

Bot data: {"patchset_id": 1, "attempt_start_ts": 1487956338218210, "parent_rev":
"fdaa8706aed3503cd67080bc2df1e067412d196e", "commit_rev":
"3ba1a8cd1b875dc7bfcb7075fe4f78d0dfe0ff98"}

[commit-bot: I haz the power, 2017-02-24 17:12:35]

Description was changed from

==========
Revert of Use sched_yield on all POSIX platforms in PlatformThread. (patchset #1
id:1 of https://codereview.webrtc.org/2716683002/ )

Reason for revert:
Reverting this change since it didn't affect the perf regressions we were seeing
and actually seems to have caused more regressions as per comment in the bug.

Original issue's description:
> Use sched_yield on all POSIX platforms in PlatformThread.
> (not only MacOS)
> 
> This is a test to see if perf regressions we're seeing may be related to the
use of nanosleep().
> 
> BUG=695438
> TBR=solenberg@webrtc.org
> 
> Review-Url: https://codereview.webrtc.org/2716683002 .
> Cr-Commit-Position: refs/heads/master@{#16807}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/384498abb5a0dc3e871e437e5...

TBR=solenberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=695438
==========

to

==========
Revert of Use sched_yield on all POSIX platforms in PlatformThread. (patchset #1
id:1 of https://codereview.webrtc.org/2716683002/ )

Reason for revert:
Reverting this change since it didn't affect the perf regressions we were seeing
and actually seems to have caused more regressions as per comment in the bug.

Original issue's description:
> Use sched_yield on all POSIX platforms in PlatformThread.
> (not only MacOS)
> 
> This is a test to see if perf regressions we're seeing may be related to the
use of nanosleep().
> 
> BUG=695438
> TBR=solenberg@webrtc.org
> 
> Review-Url: https://codereview.webrtc.org/2716683002 .
> Cr-Commit-Position: refs/heads/master@{#16807}
> Committed:
https://chromium.googlesource.com/external/webrtc/+/384498abb5a0dc3e871e437e5...

TBR=solenberg@webrtc.org
# Skipping CQ checks because original CL landed less than 1 days ago.
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=695438

Review-Url: https://codereview.webrtc.org/2712133003
Cr-Commit-Position: refs/heads/master@{#16833}
Committed:
https://chromium.googlesource.com/external/webrtc/+/3ba1a8cd1b875dc7bfcb7075f...
==========

[commit-bot: I haz the power, 2017-02-24 17:12:36]

Committed patchset #1 (id:1) as
https://chromium.googlesource.com/external/webrtc/+/3ba1a8cd1b875dc7bfcb7075f...

[tommi, 2017-02-28 10:22:14]

A revert of this CL (patchset #1 id:1) has been created in
https://codereview.webrtc.org/2725573002/ by tommi@webrtc.org.

The reason for reverting is: Relanding - using sched_yield() in PlatformThread
on all posix platforms..