REGRESSIONS housekeeping

* Changed all remaining dates from MM/DD/YY[YY] to YYYY-MM-DD
* Removed sporadic failures more than a month old or for which
  I know fixes have been filed (I may have missed others)
Updating based on tonight's cygwin returns
Merge pull request #824 from bradcray/triage-sep-blc

REGRESSIONS Housecleaning + today's Cygwin returns

New regressions
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Improvements
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* CHPL_RT_CALL_STACK_SIZE tests fixed for Cygwin (thanks Elliot!)

* Removed most sporadic failure modes that are > 1 month old, which
  is the policy I'm going to propose going forward.

* Also removed sporadic failures that I believe a fix has been filed
  for.  If there are others that you think should similarly be
  removed, give a shout.

Misc
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* Changed all dates from MMM/DD/YY[YY] to YYYY-MM-DD format