SQLiteDatabase: fix inconsistent locking

Synchronized blocks should never call lock() or any operation that
does it. otherwise, bugs like bug:3032897 will occur.
Remove synchronization on all methods in SQLiteStatement
and SQLiteProgram because the caller is supposed to
do the synchronization if the same SQLiteStatement or
SQLiteQuery (which extends SQLiteProgram) object
is used by more than one thread at the same time.
(documentation on SQLiteStatement, SQLiteProgram
mentions this note)

Change-Id: Ifd6ee94d743c38c187e2eb778c57076da7a15073