RFR: 8185855: Debug exception stacks should be clearer

[Seán Coffey]

Looking to improve the stacktrace output made when debug mode is enabled 
for java.security and sun.security classes. In the past, some of these 
have led to confusion for end users. Best to add some context when we're 
printing stacktrace for informational, debug, purposes.

https://bugs.openjdk.java.net/browse/JDK-8185855

webrev : http://cr.openjdk.java.net/~coffeys/webrev.8185855/webrev/

The one minor functional change I've made is in 
sun/security/util/AnchorCertificates.java

I figured that it's best to print some context around a stacktrace that 
we're about to print rather than print it only in debug mode.

regards,
Sean.