RFR (XS) JDK-8033584: Remove java/lang/reflect/Method/invoke/TestPrivateInterfaceMethodReflect.java from exclude list

[Lois Foltan]

Please review the following change to remove a test from ProblemList.txt.

Webrev:
http://cr.openjdk.java.net/~lfoltan/bug_jdk8033584/

Bug: Remove 
java/lang/reflect/Method/invoke/TestPrivateInterfaceMethodReflect.java 
from exclude list
https://bugs.openjdk.java.net/browse/JDK-8033584

Summary:
The issue causing TestPrivateInterfaceMethodReflect.java to fail was 
fixed by the JVM Runtime team for JDK 8, for details see JDK-8029415 
<https://bugs.openjdk.java.net/browse/JDK-8029415>.

Thank you,
Lois