Add complete ElementKind information directly to Map for objects with elements.

src/ia32/full-codegen-ia32.cc

Index: src/ia32/full-codegen-ia32.cc
diff --git a/src/ia32/full-codegen-ia32.cc b/src/ia32/full-codegen-ia32.cc
index 8b941e9a3a8e6a1af90127117d70173cec9916c8..56cc80abc2f820af10ef7527452b5f3934aa8e58 100644
--- a/src/ia32/full-codegen-ia32.cc
+++ b/src/ia32/full-codegen-ia32.cc
@@ -3371,9 +3371,7 @@ void FullCodeGenerator::EmitFastAsciiArrayJoin(ZoneList<Expression*>* args) {
   __ j(not_equal, &bailout);
 
   // Check that the array has fast elements.
-  __ test_b(FieldOperand(scratch, Map::kBitField2Offset),
-            1 << Map::kHasFastElements);
-  __ j(zero, &bailout);
+  __ CheckFastElements(scratch, &bailout);
 
   // If the array has length zero, return the empty string.
   __ mov(array_length, FieldOperand(array, JSArray::kLengthOffset));