Disable TCMalloc for Windows

      We want to see what is the performace hit on Windows when we disable it
and fall back to the CRT allocator which uses the LFH Windows Heap.

I expect some turbulence in the perf bots.

BUG=434397

Review URL: https://codereview.chromium.org/722073003

Cr-Commit-Position: refs/heads/master@{#305567}