[stubs] Use CSA::IsHeapNumberMap() instead of manual map comparing.

src/builtins/builtins-global.cc

Index: src/builtins/builtins-global.cc
diff --git a/src/builtins/builtins-global.cc b/src/builtins/builtins-global.cc
index c65b3b6428a079897ccfc9bd0ab3886bc191d761..27d2d3b8b3445bb45c59a5e714341e68ffdd06fe 100644
--- a/src/builtins/builtins-global.cc
+++ b/src/builtins/builtins-global.cc
@@ -127,8 +127,7 @@ void Builtins::Generate_GlobalIsFinite(compiler::CodeAssemblerState* state) {
     // Check if {num} is a HeapNumber.
     Label if_numisheapnumber(&assembler),
         if_numisnotheapnumber(&assembler, Label::kDeferred);
-    assembler.Branch(assembler.WordEqual(assembler.LoadMap(num),
-                                         assembler.HeapNumberMapConstant()),
+    assembler.Branch(assembler.IsHeapNumberMap(assembler.LoadMap(num)),
                      &if_numisheapnumber, &if_numisnotheapnumber);
 
     assembler.Bind(&if_numisheapnumber);
@@ -182,8 +181,7 @@ void Builtins::Generate_GlobalIsNaN(compiler::CodeAssemblerState* state) {
     // Check if {num} is a HeapNumber.
     Label if_numisheapnumber(&assembler),
         if_numisnotheapnumber(&assembler, Label::kDeferred);
-    assembler.Branch(assembler.WordEqual(assembler.LoadMap(num),
-                                         assembler.HeapNumberMapConstant()),
+    assembler.Branch(assembler.IsHeapNumberMap(assembler.LoadMap(num)),
                      &if_numisheapnumber, &if_numisnotheapnumber);
 
     assembler.Bind(&if_numisheapnumber);