Fix issue in tf.image.extract_glimpse (#12829)

* Fix issue in tf.image.extract_glimpse

This fix tries to fix the issue raised in 2134 where
`tf.image.extract_glimpse` does not work as expected
when `centered=False` and `normalized=False`

This fix fixes 2134.

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

* Add test cases for tf.image.extract_glimpse

Add test cases for tf.image.extract_glimpse with
centered=False and normalized=False

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