golancilint: add paralleltest linter
In some of our tests we don't reinitialize the test variable, this can cause problems to go undetected (https://gist.github.com/posener/92a55c4cd441fc5e5e85f27bca008721). This MR plans to do the following:
- Fix all tests which have this issue
- Add paralleltest linter to avoid this issue in the future.
Closes: #4673 (closed)
Edited by Karthik Nayak