test.py: respect --verbose even if output is a tty
test.py: respect --verbose even if output is a tty

If output is a not a tty, verbose is set automatically.

If the output is a tty, one has to request --verbose.

However, a part of test.py verbosity was ignoring --verbose
and looking only at the terminal type.

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla