Use a different map to distinguish eval contexts

test/mjsunit/regress/regress-5736.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.
 
 var my_global = 0;
 
 // The problem was that we allowed lazy functions inside evals, but did not
 // force context allocation on the eval scope. Thus, foo was not context
 // allocated since we didn't realize that a lazy function referred to it.
 eval(`let foo = 1;
       let maybe_lazy = function() { foo = 2; }
       maybe_lazy();
       my_global = foo;`);
 assertEquals(2, my_global);
 
 (function TestVarInStrictEval() {
   "use strict";
   eval(`var foo = 3;
         let maybe_lazy = function() { foo = 4; }
         maybe_lazy();
         my_global = foo;`);
   assertEquals(4, my_global);
 })();
+
+eval("let foo = 1; function lazy() { foo = 2; } lazy(); my_global = foo;");
+assertEquals(my_global, 2);