Using GetMoreGeneralElementsKind in more places

src/builtins.cc

Index: src/builtins.cc
diff --git a/src/builtins.cc b/src/builtins.cc
index 4ad6c2117c68b581f5dbdf2f296f0644c47774d3..a4fcdaf76a5c6cc47be9bd16e05596a780bb0e77 100644
--- a/src/builtins.cc
+++ b/src/builtins.cc
@@ -1228,19 +1228,15 @@ Object* Slow_ArrayConcat(Arguments* args, Isolate* isolate) {
       if (length_estimate != 0) {
         ElementsKind array_kind =
             GetPackedElementsKind(array->map()->elements_kind());
-        if (IsMoreGeneralElementsKindTransition(kind, array_kind)) {
-          kind = array_kind;
-        }
+        kind = GetMoreGeneralElementsKind(kind, array_kind);
       }
       element_estimate = EstimateElementCount(array);
     } else {
       if (obj->IsHeapObject()) {
         if (obj->IsNumber()) {
-          if (IsMoreGeneralElementsKindTransition(kind, FAST_DOUBLE_ELEMENTS)) {
-            kind = FAST_DOUBLE_ELEMENTS;
-          }
-        } else if (IsMoreGeneralElementsKindTransition(kind, FAST_ELEMENTS)) {
-          kind = FAST_ELEMENTS;
+          kind = GetMoreGeneralElementsKind(kind, FAST_DOUBLE_ELEMENTS);
+        } else {
+          kind = GetMoreGeneralElementsKind(kind, FAST_ELEMENTS);
         }
       }
       length_estimate = 1;