Add unit test for VCALENDAR generation from TimeZone

* Sanity check runs through every TimeZone and makes sure that there
  are no exceptions thrown
* Also, that we find at least 10x as many TimeZone's with RRULEs as
  those without (empirical)

Change-Id: I2f266ac9d2a839f053bb5fda10a5b77dc8dd2c04
1 file changed