Add timeit.bat to tools\win

timeit.bat is a simple batch file that times whatever command you pass
to it. It uses a helper python script to do the math at the end. There
is no error checking so don't make mistakes.

R=dcheng@chromium.org

Review-Url: https://codereview.chromium.org/2820843002
Cr-Original-Commit-Position: refs/heads/master@{#464815}
Cr-Mirrored-From: https://chromium.googlesource.com/chromium/src
Cr-Mirrored-Commit: 8811aed463ee87b0302ff8a80a730ebd86dee515
2 files changed