[HOTFIX] Add static import to fix build break from #7676.

core/src/main/java/org/apache/spark/util/collection/unsafe/sort/PrefixComparators.java

@@ -23,6 +23,7 @@ import org.apache.spark.annotation.Private;
 import org.apache.spark.unsafe.PlatformDependent;
 import org.apache.spark.unsafe.types.UTF8String;
 import org.apache.spark.util.Utils;
+import static org.apache.spark.unsafe.PlatformDependent.BYTE_ARRAY_OFFSET;
 
 @Private
 public class PrefixComparators {