[heap] Use size_t for heap and space counters.

test/cctest/heap/test-spaces.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 453 matching lines @@
 
   HeapObject* ho = HeapObject::cast(obj);
 
   CHECK(lo->Contains(HeapObject::cast(obj)));
 
   CHECK(lo->FindObject(ho->address()) == obj);
 
   CHECK(lo->Contains(ho));
 
   while (true) {
-    intptr_t available = lo->Available();
+    size_t available = lo->Available();
     { AllocationResult allocation = lo->AllocateRaw(lo_size, NOT_EXECUTABLE);
       if (allocation.IsRetry()) break;
     }
     // The available value is conservative such that it may report
     // zero prior to heap exhaustion.
     CHECK(lo->Available() < available || available == 0);
   }
 
   CHECK(!lo->IsEmpty());
 
@@ skipping 307 matching lines @@
   HeapObject* filler =
       HeapObject::FromAddress(array->address() + array->Size());
   CHECK_EQ(filler->map(), CcTest::heap()->two_pointer_filler_map());
 
   const size_t shrinked = page->ShrinkToHighWaterMark();
   CHECK_EQ(0u, shrinked);
 }
 
 }  // namespace internal
 }  // namespace v8