Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54178
Protect against AsyncListeners that throw RuntimeExceptions (they should normally only throw IOExceptions).
Includes a test case.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@1471371 13f79535-47bb-0310-9956-ffa450edef68