[turbofan] Introduce a SpeculativeToNumber operator.

src/compiler/simplified-operator.h

Index: src/compiler/simplified-operator.h
diff --git a/src/compiler/simplified-operator.h b/src/compiler/simplified-operator.h
index ed4f0cfe3dfd1b045e55db14296301f64d595956..bcbcefd3a8b29753300e943f47e248d0d7888e7c 100644
--- a/src/compiler/simplified-operator.h
+++ b/src/compiler/simplified-operator.h
@@ -359,6 +359,8 @@ class V8_EXPORT_PRIVATE SimplifiedOperatorBuilder final
   const Operator* StringFromCodePoint(UnicodeEncoding encoding);
   const Operator* StringIndexOf();
 
+  const Operator* SpeculativeToNumber(NumberOperationHint hint);
+
   const Operator* PlainPrimitiveToNumber();
   const Operator* PlainPrimitiveToWord32();
   const Operator* PlainPrimitiveToFloat64();