Change evmtool eof-test handling of empty code (#7675)

In EOFTest, treat empty code as invalid.

Signed-off-by: Danno Ferrin <danno@numisight.com>

ethereum/evmtool/src/main/java/org/hyperledger/besu/evmtool/EOFTestSubCommand.java

@@ -224,7 +224,7 @@ public class EOFTestSubCommand implements Runnable {
       return failed(re.getMessage());
     }
     if (codeBytes.isEmpty()) {
-      return passed();
+      return failed("invalid_magic code is zero-length");
     }
 
     var layout = EOFLayout.parseEOF(codeBytes);