Add post_run_target for ShadowExecutor (#1641)

Author: tokatoka

libafl/src/executors/shadow.rs

@@ -70,7 +70,9 @@ where
         mgr: &mut EM,
         input: &Self::Input,
     ) -> Result<ExitKind, Error> {
-        self.executor.run_target(fuzzer, state, mgr, input)
+        let ret = self.executor.run_target(fuzzer, state, mgr, input);
+        self.executor.post_run_reset();
+        ret
     }
 }