Add a simple python script to generate a new test (#3972)
Add a simple python script to generate a new test (#3972)

The current default citus settings for tests are not really best
practice anymore. However, we keep them because lots of tests depend on
them.

I noticed that I created the same test harness for new tests I added all
the time. This is a simple script that generates that harness, given a
name for the test.

To run:

src/test/regress/bin/create_test.py my_awesome_test
citusdata/citus,citusdata/citus,citusdata/citus,citusdata/citus,citusdata/citus