[SPARK-2050 - 2][SQL] DIV and BETWEEN should not be case sensitive.

Followup: #989

Author: Michael Armbrust <michael@databricks.com>

Closes #994 from marmbrus/caseSensitiveFunctions2 and squashes the following commits:

9d9c8ed [Michael Armbrust] Fix DIV and BETWEEN.

(cherry picked from commit 8d210560be8b143e48abfbaca347f383b5aa4798)
Signed-off-by: Michael Armbrust <michael@databricks.com>