HPCC-10245 Add current tests which pass

Add 266 test cases from the old regression suite. All of them passed on all
clusters: thor, hthor and roxie.

Change regression suite code to simplified usage:

- Add ‘.’ (current directory) to default value of  –suiteDir parameter in run.
- Add thor to default value of –cluster parameter in query.

Update README.rst.

Signed-off-by: Attila Vamos <attila.vamos@gmail.com>