Fix all the code which has duplicate variable declarations

fpdfsdk/jsapi/fxjs_v8_embeddertest.cpp

 // Copyright 2015 PDFium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "testing/gtest/include/gtest/gtest.h"
 #include "testing/js_embedder_test.h"
 
 namespace {
 
 const double kExpected0 = 6.0;
@@ skipping 46 matching lines @@
   FXJS_InitializeRuntime(isolate(), nullptr, &global_context2,
                          &static_objects2);
 
   v8::Context::Scope context_scope(GetV8Context());
   ExecuteInCurrentContext(kScript0);
   CheckAssignmentInCurrentContext(kExpected0);
 
   {
     v8::Local<v8::Context> context1 =
         v8::Local<v8::Context>::New(isolate(), global_context1);
-    v8::Context::Scope context_scope(context1);
+    v8::Context::Scope context_scope1(context1);
     ExecuteInCurrentContext(kScript1);
     CheckAssignmentInCurrentContext(kExpected1);
   }
   FXJS_ReleaseRuntime(isolate(), &global_context1, &static_objects1);
 
   {
     v8::Local<v8::Context> context2 =
         v8::Local<v8::Context>::New(isolate(), global_context2);
-    v8::Context::Scope context_scope(context2);
+    v8::Context::Scope context_scope2(context2);
     ExecuteInCurrentContext(kScript2);
     CheckAssignmentInCurrentContext(kExpected2);
   }
   FXJS_ReleaseRuntime(isolate(), &global_context2, &static_objects2);
 
   CheckAssignmentInCurrentContext(kExpected0);
 }