RFR: JDK-8210560: [TEST] convert com/sun/jdi redefineClass-related tests

[Alex Menkov]

Hi,

Please review a fix for
https://bugs.openjdk.java.net/browse/JDK-8210560
webrev:
http://cr.openjdk.java.net/~amenkov/sh2java/redefineClasses1/webrev.01/

New class (ClassTransformer) was developed to implement simple class 
transformer for class redefinition (the same functionality as 
implemented by ShellScaffold.sh).

Both setBreakpoint and redefineClass require source file name, so 
JdbTest class was updated to accept it as ctor argument and use by 
corresponding methods.

--alex