Add missing right paren in assertion log messages

Change-Id: Ia6f3f0f74b6de127d8989935e10c15a6cf52e5d7
Add a test listener that outputs failures to stderr as they happen

Makes them intermix properly with debugging output from the tested
functionality.

After the test has run, don't repeat the failure messages, just print a short
summary.

Change-Id: I6b491d3a34094df2da11df5e404adb63299de342