[tools/perf] Add speedometer2-future to the CQ blacklist

The test is very flaky on the CQ.

Bug: chromium:1003776
Change-Id: Iba048e05b26213272b9f74375cedd7d62adf117f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1808162Reviewed-by: Caleb Rouleau <crouleau@chromium.org>
Commit-Queue: Rakib Hasan <rmhasan@google.com>
Cr-Commit-Position: refs/heads/master@{#697015}

tools/perf/benchmarks/benchmark_smoke_unittest.py

@@ -114,6 +114,7 @@ _BLACK_LIST_TEST_NAMES = [
    'tab_switching.typical_25',
    'UNSCHEDULED_oortonline_tbmv2',
    'webrtc',  # crbug.com/932036
+   'speedometer2-future' # Flaky on mac, crbug.com/1003776
 ]