RFR 8198533 Remove obsolete JDIScaffold class from repo

[Paru Somashekar]

Hi

Please review fix for JDK-8198533
While removing obsolete JDIScaffold class, found one more class : 
NativeInstanceFilter, that needed to be updated to use TestScaffold.

Bug : JDK-8198533 <https://bugs.openjdk.java.net/browse/JDK-8198533>
Webrev : http://cr.openjdk.java.net/~psomashe/8198533/webrev/ 
<http://cr.openjdk.java.net/%7Epsomashe/8198533/webrev/>

thanks,
Paru.