RFR 9 7180225 : SecurityExceptions not defined in some class loader methods

[Brent Christian]

Hi,

Please review this change which does some cleanup around documenting 
conditions for throwing SecurityExceptions.

It adds a missing @throws tag to Class.forName(String, boolean, 
ClassLoader), and consolidates specifics in the @throws tags of 
ClassLoader & Thread.

Bug:      https://bugs.openjdk.java.net/browse/JDK-7180225
Webrev:   http://cr.openjdk.java.net/~bchristi/7180225/webrev.01/webrev/
Specdiff: 
http://cr.openjdk.java.net/~bchristi/7180225/webrev.01/specdiff/package-summary.html

Thanks!

-Brent