Added unit test to verify num vals in str_to_num
Added unit test to verify num vals in str_to_num

Added new unit test to verify that an int is of type numbers.Number
when an int is passed into translator.common.utils.str_to_num()

Change-Id: Ibce8a3c6fd60a337b39181ab1d9f3edc2ddc79a8

openstack/tosca-parser,openstack/tosca-parser,openstack/heat-translator,openstack/heat-translator