RFR(XXS): JDK-8141331 - Test hotspot/compiler/oracle/MethodMatcher.java fails with NPE

[Dmitrij Pochepko]

Hi,

please review fix for https://bugs.openjdk.java.net/browse/JDK-8141331 - 
Test hotspot/compiler/oracle/MethodMatcher.java fails with NPE

A small fix adds @build directive to have WhiteBox compiled and fix the test

a webrev: http://cr.openjdk.java.net/~dpochepk/8141331/webrev.01/

Thanks,
Dmitrij