Fix SimpleDateFormatTest when run outside California

If the device was set to a timezone besides America/Los_Angeles
the test would fail. Under cts-tradefed the SimpleDateFormat
was being created at class load time (using the device default)
and then the timezone default was being set to
America/Los_Angeles during setUp().

Contains refactoring to remove nested test case and
reformatting.

Change-Id: I26a7a2c6ce0d6205cf6d20c9b4cbebf550da19ce
1 file changed