Allow Calendar.getInstance to be called with a null Locale.

LocaleData.get was changed to throw for null locales instead
of falling back to the default, so we need to adjust callers
accordingly.

Turns out all other callers would've thrown anyway (for different
reasons) so this change makes those exceptions explicit and
adds tests for them.

bug: 16938922

(cherry picked from commit 148de94b69ad9ed98ebb1adf0e8eb1b1e9e33e1f)

Change-Id: Id89961c9b9524776ef13f57d97b2bb73e19b4eb1
9 files changed