JDK 9 RFR of JDK-8042849: Fix raw and unchecked warnings in com.sun.java.swing

[Joe Darcy]

Hello,

As a follow-up to the other recent lint warning fixes in swing, please 
review the next chunk of cleanup:

    JDK-8042849: Fix raw and unchecked warnings in com.sun.java.swing
    http://cr.openjdk.java.net/~darcy/8042849.0/

Thanks,

-Joe