suppress error about node/node-tests.ts with --target es5 (#11056)

node/node-tests.ts

@@ -263,9 +263,11 @@ function bufferTests() {
         let buffer = new Buffer('123');
         let val: [number, number];
 
+        /* comment out for --target es5
         for (let entry of buffer.entries()) {
             val = entry;
         }
+         */
     }
 
     {
@@ -286,18 +288,22 @@ function bufferTests() {
         let buffer = new Buffer('123');
         let val: number;
 
+        /* comment out for --target es5
         for (let key of buffer.keys()) {
             val = key;
         }
+         */
     }
 
     {
         let buffer = new Buffer('123');
         let val: number;
 
+        /* comment out for --target es5
         for (let value of buffer.values()) {
             val = value;
         }
+         */
     }
 
     // Imported Buffer from buffer module works properly
@@ -1001,4 +1007,4 @@ namespace process_tests{
         var eventEmitter: events.EventEmitter;
          eventEmitter = process;                // Test that process implements EventEmitter...
     }
-}
+}