Add quiet mode to testing.util.run_opts

Placed next to verbose due to logical connection.
This is not part of a public API so the change
should not matter - the tests all seem to pass
arguments by name anyway.

testing/util.py

@@ -46,6 +46,7 @@ def run_opts(
         files=(),
         color=False,
         verbose=False,
+        quiet=False,
         hook=None,
         from_ref='',
         to_ref='',
@@ -63,6 +64,7 @@ def run_opts(
         files=files,
         color=color,
         verbose=verbose,
+        quiet=quiet,
         hook=hook,
         from_ref=from_ref,
         to_ref=to_ref,