Remove now-unnecessary msvs_cygwin_shell

Added https://src.chromium.org/viewvc/chrome?view=rev&revision=237636
but now unnecessary since we build on ninja everywhere.

TBR=wez@chromium.org
BUG=123026

Review URL: https://codereview.chromium.org/139303024

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245747 0039d316-1c4b-4281-b951-d872f2087c98
[Telemetry] Properly handle retries after browser crash.

Previously it was easy for the results to get into a bad state and assert in a
variety of ways.

This ensures we ignore the partial results in the case of a crash.

BUG=

Review URL: https://codereview.chromium.org/140773004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@245748 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 245748