Prepare migrating testing auxiliary functions from tests to testutil. Remove local duplicates on testutil.WriteToNewTempFile(). Always favor testutil.NewTestCaseDir() over ioutil.TempDir(). Add test cases for the testing auxiliary functions.
* Remove viper * Remove viper * Remove viper * Skip TestCLIValidateGenesis * remove cruft leftover Co-authored-by: Alessio Treglia <alessio@tendermint.com>