Add missing empty.txt file for recent set of tests.
Add missing empty.txt file for recent set of tests.

common-workflow-language/common-workflow-language,common-workflow-language/common-workflow-language,common-workflow-language/common-workflow-language,mr-c/common-workflow-language,mr-c/common-workflow-language,curoverse/common-workflow-language,dleehr/common-workflow-language,curoverse/common-workflow-language,dleehr/common-workflow-language,dleehr/common-workflow-language,mr-c/common-workflow-language,dleehr/common-workflow-language,common-workflow-language/common-workflow-language