Avoid NPE when using JSP unloading and tag files.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1428358 13f79535-47bb-0310-9956-ffa450edef68
Fix https://issues.apache.org/bugzilla/show_bug.cgi?id=54370
Improve handling of nulls when trying to match sets of parameters to a method in EL.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/tc7.0.x/trunk@1428408 13f79535-47bb-0310-9956-ffa450edef68