Tests for Calendar APIs from OpenJDK8u60

This covers:

 - GregorianCalendar.{from,to}ZonedDateTime()
 - Calendar.toInstant()
 - Calendar.getAvailableCalendarTypes()

Notes:
 - The supported calendar types may change in a follow-up CL
   (bug 35138741). Currently, only "gregory" is listed even
   though Calendar.Builder.build() still attempts to use
   "buddhist" (this inconsistency is a bug).
 - Calendar.Builder is not covered by these tests

Test: CalendarTest, GregorianCalendarTest
Bug: 34923731
Bug: 29935305

Change-Id: Icfa87f465941e63f11f4ef6c35f82cdbcfd313fb
2 files changed