[turbofan] Introduce NumberFloor simplified operator.

src/compiler/simplified-operator.cc

Index: src/compiler/simplified-operator.cc
diff --git a/src/compiler/simplified-operator.cc b/src/compiler/simplified-operator.cc
index d60efb4068057fdfbaf4bcd7ac5227f0742e1535..460f147fa46474789ab165e1d5a01dcd3d774770 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -173,6 +173,7 @@ const ElementAccess& ElementAccessOf(const Operator* op) {
   V(NumberShiftLeft, Operator::kNoProperties, 2)         \
   V(NumberShiftRight, Operator::kNoProperties, 2)        \
   V(NumberShiftRightLogical, Operator::kNoProperties, 2) \
+  V(NumberFloor, Operator::kNoProperties, 1)             \
   V(NumberToInt32, Operator::kNoProperties, 1)           \
   V(NumberToUint32, Operator::kNoProperties, 1)          \
   V(NumberIsHoleNaN, Operator::kNoProperties, 1)         \