[turbofan] Remove the FloatXXSubPreserveNan operators.

src/compiler/typer.cc

Index: src/compiler/typer.cc
diff --git a/src/compiler/typer.cc b/src/compiler/typer.cc
index ade80e7495197d5a47c072609d2ce2cd3241013d..daa64f8ba606ccf62d93b3ebdf4f003a4e595d5a 100644
--- a/src/compiler/typer.cc
+++ b/src/compiler/typer.cc
@@ -2034,10 +2034,6 @@ Type* Typer::Visitor::TypeFloat32Add(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat32Sub(Node* node) { return Type::Number(); }
 
-Type* Typer::Visitor::TypeFloat32SubPreserveNan(Node* node) {
-  return Type::Number();
-}
-
 Type* Typer::Visitor::TypeFloat32Neg(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat32Mul(Node* node) { return Type::Number(); }
@@ -2073,10 +2069,6 @@ Type* Typer::Visitor::TypeFloat64Add(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat64Sub(Node* node) { return Type::Number(); }
 
-Type* Typer::Visitor::TypeFloat64SubPreserveNan(Node* node) {
-  return Type::Number();
-}
-
 Type* Typer::Visitor::TypeFloat64Neg(Node* node) { return Type::Number(); }
 
 Type* Typer::Visitor::TypeFloat64Mul(Node* node) { return Type::Number(); }