Multiple applets used different VMs/session keystore and classloader caching issues with latest 7u21 nightly build

It seems jp2launcher security fix https://jbs.oracle.com/bugs/browse/JDK-8001062 has introduced a regression which has caused no of issues e.g. multiple applets in the same page always run inside different VM.
Due to this regression following is not working
- classloader caching(feature used heavily by some popular applets e.g. pogo)
- it has also broken the fix against "JDK-8008350 Multiple same unsigned applets loaded simultaneously will cause multiple sec warning dialogs"
- Session keystore (per browser session) is not working at all
and all this is causing more than 100 new failures under Plug-in test base

Steps to reproduce
----------------------------
1)Install 7u21 nightly build
2) Try to load following applet
http://sqeweb.sfbay.sun.com/deployment2/jitu/plug-bug/ALC/PrintThread.html
If you can see 4 different VM sessions and 4 dialogs ,then issue is reproduced

Also try following classloader caching applet:
http://sqeweb.sfbay.sun.com/deployment2/jitu/plug-bug/ALC/SimpleCLCacheEnableTest.html
- Accept security warning
Once applet is loaded , do a page reload
- If you see a security warning again then bug is reprouced for session keytsore
- Also if static value ,displayed inside applet area, stays at "3" on every page reload then classloader caching issues is reproduced too

For signed keystore regression, try to load following applet
http://sqeweb.sfbay.sun.com/deployment2/jitu/plug-bug/security/file/exec/AppletFullJavaVersion.html
Accept security wanting
Do a page reload, and if security warning appears again then bug is reproduced