Extract string constants to StringConstants file

I created StringConstant file and put all the string constant in
BuildStatus and RunStatus there. Please take a look
Merge pull request #3391 from theanh0512/extracStringConstants

Extract string constants to StringConstants file
Merge remote-tracking branch 'upstream/master' into DynamoCoreSplit
Fix failing Formula node tests
Assert inconclusive on close 1 node hole test
Remove unused test dyn file, assign test to Failure category for node collapsing