[TurboFan] Improved unit test for optimized Array.prototype.map.

Test mjsunit/optimized-map walked an array through different
ElementsKind transitions, but it failed to verify that the
expected ElementsKind was in place. Although we have a regression
test for the bug, it's a good idea to make sure the basic
test covers all paths.

Bug: chromium:747075
Change-Id: I1424880801857f3356bfd63839d351d6fd1521e0
Reviewed-on: https://chromium-review.googlesource.com/584837Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#46933}

test/mjsunit/optimized-map.js

@@ -367,13 +367,10 @@ var c = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25];
       if (i < 5) {
         // First transition the output array to PACKED_DOUBLE_ELEMENTS.
         return v + 0.5;
-      } else if (i < 10) {
+      } else {
         // Then return smi values and make sure they can live in the double
         // array.
         return v;
-      } else {
-        // Later, to PACKED_ELEMENTS.
-        return v + 'hello';
       }
     }
     return c.map(callback);
@@ -382,11 +379,42 @@ var c = [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25];
   to_double();
   %OptimizeFunctionOnNextCall(to_double);
   var output = to_double();
+  assertTrue(%HasDoubleElements(output));
+  assertEquals(1.5, output[0]);
+  assertEquals(6, output[5]);
   assertEquals(975, result);
-  assertEquals("11hello", output[10]);
   assertOptimized(to_double);
 })();
 
+(function() {
+  var result = 0;
+  var to_fast = function() {
+    var callback = function(v,i,o) {
+      result += v;
+      if (i < 5) {
+        // First transition the output array to PACKED_DOUBLE_ELEMENTS.
+        return v + 0.5;
+      } else if (i < 10) {
+        // Then return smi values and make sure they can live in the double
+        // array.
+        return v;
+      } else {
+        // Later, to PACKED_ELEMENTS.
+        return v + 'hello';
+      }
+    }
+    return c.map(callback);
+  }
+  to_fast();
+  to_fast();
+  %OptimizeFunctionOnNextCall(to_fast);
+  var output = to_fast();
+  %HasObjectElements(output);
+  assertEquals(975, result);
+  assertEquals("11hello", output[10]);
+  assertOptimized(to_fast);
+})();
+
 // Messing with the Array species constructor causes deoptimization.
 (function() {
   var result = 0;