Expose ContentProviderOperation type

CHANGE
isInsert, isDelete, isUpdate, isAssertQuery

JUSTIFICATION
The use of getType() in lots of unit tests means that
ContentProviderOperation#getType() can't practically be
removed.

Why not make it public? This allows 3p to use getType() in
unit tests. Plus it allows the unbundled contacts app
to continue using getType() in order to handle TYPE_INSERT
specially, without needing to awkwardly pass isInsert values
around.

Bug: 18777272
Change-Id: I3265193cda0c9405f6df896cd96a10df7225445a