Minimizer fix (#2500)

* Clear potentially out of date id

* fmt

* add mut

libafl/src/corpus/minimizer.rs

@@ -238,6 +238,8 @@ where
                     .scheduler_mut()
                     .on_remove(state, id, &Some(removed))?;
             }
+
+            *state.corpus_mut().current_mut() = None; //we may have removed the current ID from the corpus
             Ok(())
         } else {
             Err(Error::unknown("Corpus minimization failed; unsat."))