[OpenJDK 2D-Dev] RFR: 8172813 test/java/awt/font/JNICheck/JNICheck.sh fails on Linux

[Phil Race]

Bug : https://bugs.openjdk.java.net/browse/JDK-8172813
Webrev : http://cr.openjdk.java.net/~prr/8172813/

- Clear local refs once we are done with them.
- Use grep to filter out from the log unrelated warnings as separately 
reported here :

https://bugs.openjdk.java.net/browse/JDK-8131136

-phil.