RFR: 8042872: Fix raw and unchecked warnings in sun.applet

Hi, Please review another webrev to clean up rawtypes and unchecked warning, this time for sun.applet. The webrev applied to both jdk9/dev and jdk9/client cleanly, I am not sure which repo should the webrev go once pass review. Webrev can be found at http://cr.openjdk.java.net/~henryjen/jdk9/8042872/0/webrev/ Please also let me know any particular test I should do other than regular jprt. Cheers, Henry