ES6: Update unscopables to match spec

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 191bad301e3105b16d8cfa0b9c30439e3aaf265f..8a03ef481eeb2a074d07b24c92c17a6b74291f4a 100644
--- a/test/mjsunit/harmony/proxies-with-unscopables.js
+++ b/test/mjsunit/harmony/proxies-with-unscopables.js
@@ -74,12 +74,17 @@ function TestUseProxyAsUnscopables() {
   var calls = 0;
   var proxy = Proxy.create({
     has: function(key) {
-      calls++;
-      assertEquals('x', key);
-      return calls === 2;
+      assertUnreachable();
     },
     getPropertyDescriptor: function(key) {
-      assertUnreachable();
+      calls++;
+      assertEquals('x', key);
+      return {
+        value: calls === 2 ? true : undefined,
+        configurable: true,
+        enumerable: true,
+        writable: true,
+      };
     }
   });
 
@@ -107,12 +112,12 @@ function TestThrowInHasUnscopables() {
   var calls = 0;
   var proxy = Proxy.create({
     has: function(key) {
-      if (calls++ === 0) {
-        throw new CustomError();
-      }
       assertUnreachable();
     },
     getPropertyDescriptor: function(key) {
+      if (calls++ === 0) {
+        throw new CustomError();
+      }
       assertUnreachable();
     }
   });