Fix warnings on VS2015 x86_64 build

tests/GrMemoryPoolTest.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "Test.h"
 // This is a GPU-backend specific test
 #if SK_SUPPORT_GPU
@@ skipping 88 matching lines @@
     typedef A INHERITED;
 };
 
 // D derives from C and owns a dynamically created B
 class D : public C {
 public:
     D() {
         fB = new B();
     }
     virtual void setValues(int v) {
-        fVoidStar = reinterpret_cast<void*>(v);
+        fVoidStar = reinterpret_cast<void*>(static_cast<intptr_t>(v));
         this->INHERITED::setValues(v);
         fB->setValues(v);
     }
     virtual bool checkValues(int v) {
-        return fVoidStar == reinterpret_cast<void*>(v) &&
+        return fVoidStar == reinterpret_cast<void*>(static_cast<intptr_t>(v)) &&
                fB->checkValues(v) &&
                this->INHERITED::checkValues(v);
     }
     virtual ~D() {
         delete fB;
     }
 private:
     void*   fVoidStar;
     B*      fB;
 
@@ skipping 96 matching lines @@
             for (int i = 0; i < instanceRecs.count(); ++i) {
                 Rec& rec = instanceRecs[i];
                 REPORTER_ASSERT(reporter, rec.fInstance->checkValues(rec.fValue));
                 delete rec.fInstance;
             }
         }
     }
 }
 
 #endif