[dumpling] Add a bit more output.

There are a few more steps to actually report a thing as differential
but I don't want to miss anything, so I will print it here too.

Bug: 441467877
Change-Id: I009ed1792ae486e55cbd65bf63c0863077a6a375
Reviewed-on: https://chrome-internal-review.googlesource.com/c/v8/fuzzilli/+/9012880
Reviewed-by: Michael Achenbach <machenbach@google.com>
Commit-Queue: Danylo Mocherniuk <mdanylo@google.com>

Author: Danylo Mocherniuk

Sources/Fuzzilli/Fuzzer.swift

@@ -1138,7 +1138,20 @@ public class Fuzzer {
 
             let unoptimizedDump = try String(contentsOfFile: unoptPath, encoding: .utf8)
 
-            return DiffExecution.diff(optExec: execution, unoptExec: unoptExecution, optDumpOut: optimizedDump, unoptDumpOut: unoptimizedDump)
+            // While Dumpling is not super-stable we print out the program here to not miss anything.
+            let result = DiffExecution.diff(optExec: execution, unoptExec: unoptExecution, optDumpOut: optimizedDump, unoptDumpOut: unoptimizedDump)
+
+            if result.outcome == .differential {
+                logger.error("""
+                ================================================================
+                [DUMPLING]  POTENTIAL DIFFERENTIAL DETECTED
+                ================================================================
+                """)
+
+                logger.error(script)
+            }
+
+            return result
 
         } catch {
             fatalError("Critical failure: Unable to read dump files. Error: \(error)")