[turbofan] Introduce PlainPrimitiveToNumber.

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 e906acbf880043060b3e6a94f3271506f82bf462..161695e08339277a8c8668d98c46123372eabff5 100644
--- a/src/compiler/simplified-operator.cc
+++ b/src/compiler/simplified-operator.cc
@@ -212,6 +212,9 @@ BinaryOperationHints::Hint BinaryOperationHintOf(const Operator* op) {
   V(NumberIsHoleNaN, Operator::kNoProperties, 1)           \
   V(StringFromCharCode, Operator::kNoProperties, 1)        \
   V(StringToNumber, Operator::kNoProperties, 1)            \
+  V(PlainPrimitiveToNumber, Operator::kNoWrite, 1)         \
+  V(PlainPrimitiveToWord32, Operator::kNoWrite, 1)         \
+  V(PlainPrimitiveToFloat64, Operator::kNoWrite, 1)        \
   V(ChangeTaggedSignedToInt32, Operator::kNoProperties, 1) \
   V(ChangeTaggedToInt32, Operator::kNoProperties, 1)       \
   V(ChangeTaggedToUint32, Operator::kNoProperties, 1)      \