Fix perf regression with stmts (#650)

crates/nu-engine/src/eval.rs

@@ -418,6 +418,9 @@ pub fn eval_block(
         }
 
         if stmt_idx < (num_stmts) - 1 {
+            match input {
+                PipelineData::Value(Value::Nothing { .. }, ..) => {}
+                _ => {
                     // Drain the input to the screen via tabular output
                     let config = stack.get_config().unwrap_or_default();
 
@@ -464,6 +467,8 @@ pub fn eval_block(
                             }
                         }
                     };
+                }
+            }
 
             input = PipelineData::new(Span { start: 0, end: 0 })
         }