[array] speed up array.forEach and friends by directly using in-operator

src/js/macros.py

Index: src/js/macros.py
diff --git a/src/js/macros.py b/src/js/macros.py
index 3cc2d6c2b88e1092867d322ed64f1a8e70f90039..349c97ae1977f38ac99c4c9578cb6e8869c73fab 100644
--- a/src/js/macros.py
+++ b/src/js/macros.py
@@ -124,7 +124,7 @@ macro TO_PRIMITIVE_STRING(arg) = (%_ToPrimitive_String(arg));
 macro TO_NAME(arg) = (%_ToName(arg));
 macro JSON_NUMBER_TO_STRING(arg) = ((%_IsSmi(%IS_VAR(arg)) || arg - arg == 0) ? %_NumberToString(arg) : "null");
 macro HAS_OWN_PROPERTY(obj, key) = (%_Call(ObjectHasOwnProperty, obj, key));
-macro HAS_INDEX(array, index, is_array) = ((is_array && %_HasFastPackedElements(%IS_VAR(array)) && (index < array.length)) ||  (index in array));
+macro HAS_INDEX(array, index) = (index in array);
 
 # Private names.
 macro IS_PRIVATE(sym) = (%SymbolIsPrivate(sym));