RFR : JDK-8219632: Remove reference to com.sun.javadoc API in RemoveOldDoclet test

[Priya Lakshmi Muthuswamy]

Hi,

Kindly review the fix for https://bugs.openjdk.java.net/browse/JDK-8219632
webrev : http://cr.openjdk.java.net/~pmuthuswamy/8219632/webrev.00/

jdk/javadoc/tool/removeOldDoclet/RemoveOldDoclet.java tries to use 
OldDoclet.jasm which hold reference to removed API com.sun.javadoc.
As part of the fix for 
JDK-8219575(jdk/javadoc/tool/removeOldDoclet/RemoveOldDoclet test fails 
in mach5),
tried to handle the NoDefClassFoundError.

This fix removes the reference to com.sun.javadoc in test class and the 
handling of NoClassDefFoundError.
If user creates any Doclet which doesn't implement 
jdk.javadoc.doclet.Doclet, there will be error stating that its not a 
valid Doclet.

Thanks,
Priya