[turbofan] Introduce NumberFloor simplified operator.

src/compiler/pipeline.cc

Index: src/compiler/pipeline.cc
diff --git a/src/compiler/pipeline.cc b/src/compiler/pipeline.cc
index 1de88d7e1753a805685a90181b88d280359a52bf..044d9e781ddcfcfa41061b757e68d8765f738292 100644
--- a/src/compiler/pipeline.cc
+++ b/src/compiler/pipeline.cc
@@ -649,6 +649,7 @@ struct TypedLoweringPhase {
         data->info()->is_deoptimization_enabled()
             ? JSIntrinsicLowering::kDeoptimizationEnabled
             : JSIntrinsicLowering::kDeoptimizationDisabled);
+    SimplifiedOperatorReducer simple_reducer(data->jsgraph());
     CommonOperatorReducer common_reducer(&graph_reducer, data->graph(),
                                          data->common(), data->machine());
     AddReducer(data, &graph_reducer, &dead_code_elimination);
@@ -659,6 +660,7 @@ struct TypedLoweringPhase {
     AddReducer(data, &graph_reducer, &typed_lowering);
     AddReducer(data, &graph_reducer, &intrinsic_lowering);
     AddReducer(data, &graph_reducer, &load_elimination);
+    AddReducer(data, &graph_reducer, &simple_reducer);
     AddReducer(data, &graph_reducer, &common_reducer);
     graph_reducer.ReduceGraph();
   }