[heap profiler] Drop --memlog-keep-small-allocations support.

Allocation profile precision can be controlled with
--memlog-sampling-rate option.

BUG=939900

Change-Id: If8cad19a6784fe074fe37af414fe52428234dee1
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1511012
Commit-Queue: Alexei Filippov <alph@chromium.org>
Reviewed-by: Will Harris <wfh@chromium.org>
Reviewed-by: Stephen Chenney <schenney@chromium.org>
Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Reviewed-by: Erik Chen <erikchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639139}
23 files changed