Revert of Use CLOCK_REALTIME_COARSE when available. (patchset #1 id:1 of https://codereview.chromium.org/1151283005/)

Reason for revert:
[Sheriff] This leads to several failures in chromium and blocks our roll:
https://codereview.chromium.org/1154363002/

Bisect (https://codereview.chromium.org/1152553004/) points to this CL.

Please add the failing chromium trybot on a reland of this CL.

Original issue's description:
> Use CLOCK_REALTIME_COARSE when available.
>
> On systems that have CLOCK_REALTIME_COARSE with good enough resolution,
> we can avoid making a system call to get the current time; it's serviced
> from the vDSO.
>
> This is v2 of the patch.  v1 can be found at [0] but was reverted in [1]
> because of Chromium sandbox restrictions.  The necessary changes have
> been applied upstream in [2].
>
> [0] https://codereview.chromium.org/1125003002
> [1] https://codereview.chromium.org/1130083003
> [2] https://codereview.chromium.org/1133653002
>
> BUG=
> LOG=N
>
> Committed: https://crrev.com/28cea2b749f24ba33e6e0c8e343dd0d6258ee302
> Cr-Commit-Position: refs/heads/master@{#28639}

TBR=jochen@chromium.org,bmeurer@chromium.org,ben@strongloop.com
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=

Review URL: https://codereview.chromium.org/1154783003

Cr-Commit-Position: refs/heads/master@{#28656}