[turbofan] Introduce new operators Float32SubPreserveNan and Float64SubPreserveNan for wasm.

src/compiler/machine-operator.h

Index: src/compiler/machine-operator.h
diff --git a/src/compiler/machine-operator.h b/src/compiler/machine-operator.h
index e3a67606765dabd97d9e5c3c40e21032ed8f3be5..814f6c9bed1c9de10512efb54a44350e7b71df04 100644
--- a/src/compiler/machine-operator.h
+++ b/src/compiler/machine-operator.h
@@ -245,6 +245,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   // (single-precision).
   const Operator* Float32Add();
   const Operator* Float32Sub();
+  const Operator* Float32SubPreserveNan();
   const Operator* Float32Mul();
   const Operator* Float32Div();
   const Operator* Float32Sqrt();
@@ -253,6 +254,7 @@ class MachineOperatorBuilder final : public ZoneObject {
   // (double-precision).
   const Operator* Float64Add();
   const Operator* Float64Sub();
+  const Operator* Float64SubPreserveNan();
   const Operator* Float64Mul();
   const Operator* Float64Div();
   const Operator* Float64Mod();