This allows percent difference of up to 0.2 in
SamplingHeapProfilerRateAgnosticEstimates.

Bug: chromium:834832
Tbr: ofrobots@chromium.org
No-Tree-Checks: true
No-Try: true
Change-Id: I2f38ac886700eed31840dc19d65103b84d155592
Reviewed-on: https://chromium-review.googlesource.com/1019781
Commit-Queue: Ulan Degenbaev <ulan@chromium.org>
Reviewed-by: Ulan Degenbaev <ulan@chromium.org>
Cr-Commit-Position: refs/heads/master@{#52697}