Don't compile functions in a context the caller doesn't have access to

test/mjsunit/realm-property-access.js

 // Copyright 2016 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+// Flags: --restricted-realms
+
 var r = Realm.create();
 var f = Realm.eval(r, "function f() { return this }; f()");
 assertEquals(f, Realm.global(r));
 
 // Cross-origin property access throws
 assertThrows(() => f.a, TypeError);
 assertThrows(() => { 'use strict'; f.a = 1 }, TypeError);
 
 var r2 = Realm.createAllowCrossRealmAccess();
 var f2 = Realm.eval(r2, "function f() { return this }; f()");
 assertEquals(f2, Realm.global(r2));
 
 // Same-origin property access doesn't throw
 assertEquals(undefined, f2.a);
 f2.a = 1;
 assertEquals(1, f2.a);