[runtime] support new Proxy() instead of Proxy.create and install getPrototypeOf trap

test/mjsunit/harmony/proxies-with-unscopables.js

Index: test/mjsunit/harmony/proxies-with-unscopables.js
diff --git a/test/mjsunit/harmony/proxies-with-unscopables.js b/test/mjsunit/harmony/proxies-with-unscopables.js
index 8a03ef481eeb2a074d07b24c92c17a6b74291f4a..1237b2b361041cbba35d369038067d157e82c03f 100644
--- a/test/mjsunit/harmony/proxies-with-unscopables.js
+++ b/test/mjsunit/harmony/proxies-with-unscopables.js
@@ -11,7 +11,7 @@
 function TestBasics() {
   var log = [];
 
-  var proxy = Proxy.create({
+  var proxy = new Proxy({}, {
     getPropertyDescriptor: function(key) {
       log.push(key);
       if (key === 'x') {
@@ -40,7 +40,7 @@ function TestInconsistent() {
   var log = [];
   var calls = 0;
 
-  var proxy = Proxy.create({
+  var proxy = new Proxy({}, {
     getPropertyDescriptor: function(key) {
       log.push(key);
       if (key === 'x' && calls < 1) {
@@ -72,7 +72,7 @@ function TestUseProxyAsUnscopables() {
     x: 2
   };
   var calls = 0;
-  var proxy = Proxy.create({
+  var proxy = new Proxy({}, {
     has: function(key) {
       assertUnreachable();
     },
@@ -110,7 +110,7 @@ function TestThrowInHasUnscopables() {
   function CustomError() {}
 
   var calls = 0;
-  var proxy = Proxy.create({
+  var proxy = new Proxy({}, {
     has: function(key) {
       assertUnreachable();
     },
@@ -136,7 +136,7 @@ TestThrowInHasUnscopables();
 var global = this;
 function TestGlobalShouldIgnoreUnscopables() {
   global.x = 1;
-  var proxy = Proxy.create({
+  var proxy = new Proxy({}, {
     getPropertyDescriptor: function() {
       assertUnreachable();
     }