Return early when parsoid response is failure

Not having this early return was causing the error:
"Cannot read property 'statusCode' of undefined".

Change-Id: I1d99521b93719ef9eeec6641dafa4fba46aa87ab
Update README.md for individual test run

Change-Id: I922863e59a904fbdaf1ba9249d5413584425a7a4
Merge "Update README.md for individual test run"
Merge "Return early when parsoid response is failure"