GitLab

The issues that this logging was introduced to diagnose are understood
and/or resolved, so it can be removed.

Also clean up some OS_POSIX && !OS_FUCHSIA preprocessor conditionals,
and migrate TestLauncher to use the zx::job container from the SDK.

Bug: 755282, 750370, 738275, 706592
Change-Id: Iedfaa62684a0b6e8524a456766186b4122e98ae0
Reviewed-on: https://chromium-review.googlesource.com/1108483
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Scott Graham <scottmg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#569219}