RFR : 8211317: avoid memory leak in Java_sun_awt_UNIXToolkit_load_1stock_1icon

[Baesken, Matthias]

Hello ,  please review this small change .

It adds missing resource - freeing to        
Java_sun_awt_UNIXToolkit_load_1stock_1icon  .


Bug/webrev :

https://bugs.openjdk.java.net/browse/JDK-8211317

http://cr.openjdk.java.net/~mbaesken/webrevs/8211317.0/


Best regards, Matthias