Enable int16 and uint16 for reverse op (#12531)

* Enable int16 and uint16 for reverse op

This fix tries to address the issue in 12528 where
it was not possible to run uint16 on rot90 (reverse) op

The int16 and uint16 has been implemented in CPU though
they were not enabled yet.

This fix enables int16 and uint16.

This fix fixes 12528.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

* Add test cases for int16 and uint16 for reverse op.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>