The following revision refers to this bug:
  https://chromium.googlesource.com/infra/infra/+/c6e2008fc38876cf6c2a02a496fda750ea29a473

commit c6e2008fc38876cf6c2a02a496fda750ea29a473
Author: Jeffrey Li <lijeffrey@chromium.org>
Date: Thu May 17 20:55:47 2018

[Findit] Flake Analyzer - Temporary workaround to get latest regression range

The root cause of the assertion firing is the analysis had likely performed
a check for flakiness in a recent build, which came back stable. This data
point should never have been appended to begin with, as it interferes with
the rest of lookback_algorithm and the function to get the latest regression
range, etc.

The change not to append data points is much more involved, so as a temporary
workaround, disregard that data point when calculating the latest regression
range.

Bug:  843848 
Change-Id: I88d775f0f8e1964b9fc852ad281d05ba4cd3d342
Reviewed-on: https://chromium-review.googlesource.com/1063255
Commit-Queue: Jeffrey Li <lijeffrey@chromium.org>
Reviewed-by: Shuotao Gao <stgao@chromium.org>

[modify] https://crrev.com/c6e2008fc38876cf6c2a02a496fda750ea29a473/appengine/findit/model/flake/master_flake_analysis.py
[modify] https://crrev.com/c6e2008fc38876cf6c2a02a496fda750ea29a473/appengine/findit/model/flake/test/master_flake_analysis_test.py