Handle newer tzfiles by allowing for the "big bang" transition.

Handle newer tzfiles by allowing for the "big bang" transition.

In the TZ release 2014c, a new "big bang" transition time was added
to the beginning of the tzfiles. This broke the TimeZoneInfo parsing
logic because the transition time was for 13 billion years ago, which
is unrepresentable by DateTime.

To handle these new transitions, check for times really far in the past and future, and use DateTime.Min/Max to represent them.  Then skip over any DateTime.MinValue times when generating the AdjustmentRules.

Fix https://github.com/dotnet/corefx/issues/2816.