Remove isolate pointer from context objects.

runtime/vm/runtime_entry_mips.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_MIPS)
 
 #include "vm/runtime_entry.h"
 
 #include "vm/assembler.h"
@@ skipping 31 matching lines @@
 #endif
   if (is_leaf()) {
     ASSERT(argument_count == this->argument_count());
     ExternalLabel label(entry);
     __ BranchLink(&label);
   } else {
     // Argument count is not checked here, but in the runtime entry for a more
     // informative error message.
     __ LoadImmediate(S5, entry);
     __ LoadImmediate(S4, argument_count);
-    __ BranchLink(&StubCode::CallToRuntimeLabel());
+    __ BranchLink(&Isolate::Current()->stub_code()->CallToRuntimeLabel());
   }
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_MIPS