[turbofan] Recognize and optimize flooring integer division.

src/compiler/typed-optimization.h

Index: src/compiler/typed-optimization.h
diff --git a/src/compiler/typed-optimization.h b/src/compiler/typed-optimization.h
index fb2db7249dd858634419b20050dd56b7f5b0d64b..810914993f2d256fcab75c60c31ec732fa1a1d0d 100644
--- a/src/compiler/typed-optimization.h
+++ b/src/compiler/typed-optimization.h
@@ -46,6 +46,7 @@ class V8_EXPORT_PRIVATE TypedOptimization final
   Reduction ReduceCheckMaps(Node* node);
   Reduction ReduceCheckString(Node* node);
   Reduction ReduceLoadField(Node* node);
+  Reduction ReduceNumberFloor(Node* node);
   Reduction ReduceNumberRoundop(Node* node);
   Reduction ReduceNumberToUint8Clamped(Node* node);
   Reduction ReducePhi(Node* node);