tests: Use colors and dots in test_runner.py output only if standard output is a terminal -- allows for using the test runner output as input to other programs
tests: Use colors and dots in test_runner.py output only if standard output is a terminal -- allows for using the test runner output as input to other programs

Former-commit-id: 803f5674d872319c6fce227a8041abc0ae9b8ede
syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin,syscoin/syscoin