Blacklist a known failure in GregorianCalendarTest.

The issues here relate to how we deal with ambiguous wall
clock times, i.e, wall clock values that we "skip" when we
move the clock forward when transitioning into daylight
savings, and wall clock times that occur twice when we
move the clock backward

This isn't a regression. We've never handled this correctly.

bug: 12778197
Change-Id: Ida79583c02c6895096a8afdd8f59b1002b282d32
2 files changed