Fix style

Author: Zhengyu Gu

substratevm/src/com.oracle.svm.core/src/com/oracle/svm/core/heap/GCName.java

@@ -33,6 +33,7 @@
 import com.oracle.svm.core.annotate.AutomaticFeature;
 import com.oracle.svm.core.annotate.Uninterruptible;
 import com.oracle.svm.core.annotate.UnknownObjectField;
+
 /**
  * This class holds supported garbage collector names.
  */