Apply my patch from https://issues.apache.org/bugzilla/show_bug.cgi?id=48616#c20

Apply my patch from https://issues.apache.org/bugzilla/show_bug.cgi?id=48616#c20
This patch
- Reverts r905145,
- Provides an alternative fix for bug 48616 and bug 42390,
- Replaces Vector -> List, Hashtable -> HashMap in the affected API.

JspFragments are scriptless, so no need to declare or sync scripting
variables for fragments. Since errors in syncing the scripting variables for
JSP Fragments caused 48616 & 42390, this fixes both these bugs too.

git-svn-id: https://svn.apache.org/repos/asf/tomcat/trunk@910792 13f79535-47bb-0310-9956-ffa450edef68