Remove win32toolhelp.h.

Unittests flake when run in parallel, and this file isn't used.

BUG=
R=tommi@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/53659004

Cr-Original-Commit-Position: refs/heads/master@{#9368}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: e973c2a63b23997dd2312108098cfb0f410d5717
3 files changed