Don't emit accessors multiple times.

src/compiler/emitter.ts

@@ -2545,6 +2545,9 @@ module ts {
                     if (property.kind === SyntaxKind.GetAccessor || property.kind === SyntaxKind.SetAccessor) {
                         // TODO (drosen): Reconcile with 'emitMemberFunctions'.
                         var accessors = getAllAccessorDeclarations(node.properties, <AccessorDeclaration>property);
+                        if (property !== accessors.firstAccessor) {
+                            continue;
+                        }
                         write("Object.defineProperty(");
                         emit(tempVar);
                         write(", ");

tests/baselines/reference/computedPropertyNames49_ES5.js

@@ -60,15 +60,7 @@ var x = (_a = {
         enumerable: true,
         configurable: true
     }),
-    Object.defineProperty(_a, "foo", {
-        get: function () {
-            if (1 == 1) {
-                return 10;
-            }
-        },
-        enumerable: true,
-        configurable: true
-    }),
+    ,
     _a.p2 = 20,
     _a
 );

tests/baselines/reference/computedPropertyNames50_ES5.js

@@ -56,15 +56,7 @@ var x = (_a = {
         enumerable: true,
         configurable: true
     }),
-    Object.defineProperty(_a, "foo", {
-        get: function () {
-            if (1 == 1) {
-                return 10;
-            }
-        },
-        enumerable: true,
-        configurable: true
-    }),
+    ,
     _a.p2 = 20,
     _a
 );