Convert entire project to strict lexicographical import sort ordering

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=127234970

java/google/registry/util/HexDumper.java

@@ -21,7 +21,6 @@ import java.io.IOException;
 import java.io.OutputStream;
 import java.io.StringWriter;
 import java.io.Writer;
-
 import javax.annotation.Nonnegative;
 import javax.annotation.WillNotClose;
 import javax.annotation.concurrent.NotThreadSafe;