[phobos] windows tz updates breaking unit tests, again

[Vladimir Panteleev via phobos]

On Wednesday, 13 April 2016 at 18:50:31 UTC, Brad Roberts wrote:
> https://support.microsoft.com/en-us/kb/3148851
>
> This update floated through last night and is now causing the 
> Win_32 tester to fail.  The Win_32_64 will almost certainly 
> start failing as soon as the update makes its way onto that box.

Took a stab at it:
https://github.com/D-Programming-Language/phobos/pull/4196

> Why are the datetime tests so damned sensitive to external 
> system state?

Seems like the tests want to make sure that we know how to 
convert ALL Windows timezone names to their tz database 
equivalents. Not sure how much sense that makes, however the 
relevant functions are being deprecated.