Nested SLO Range Request Regression Test

* Added test test_nested_slo_range_request
  to nested_slo_test module.
* Added data generator method for use in
  range request test.
* Moved container creation to class setup

Change-Id: I15397bacbf2aabdd80c26ef8846f7b753551fcd1
Merge "Nested SLO Range Request Regression Test"