Implement maxrss for Windows

No more -1 in the first column on Windows!

E.g. http://build.chromium.org/p/client.skia/builders/Perf-Win8-ShuttleA-HD7770-x86_64-Release-Trybot/builds/0/steps/nanobench/logs/stdio

BUG=skia:

Review URL: https://codereview.chromium.org/661413004
1 file changed