Fix sign extension issues

Fix sign extension issues when reading and writing pointers to
int32_t fields.  Cast the pointer to a uint32_t to check if it
fits, and cast it through uintptr_t and uint32_t.

Bug: 36281983
Test: m -j test-art-host with LibartImgHostBaseAddress == 0xa0000000
Change-Id: Idec99dcb5a47f2633a4f14c98af8e23c46dc7052
diff --git a/runtime/mirror/array-inl.h b/runtime/mirror/array-inl.h
index f56226b..04c80c5 100644
--- a/runtime/mirror/array-inl.h
+++ b/runtime/mirror/array-inl.h
@@ -402,8 +402,8 @@
     return (T)static_cast<uintptr_t>(
         AsLongArray<kVerifyFlags, kReadBarrierOption>()->GetWithoutChecks(idx));
   }
-  return (T)static_cast<uintptr_t>(
-      AsIntArray<kVerifyFlags, kReadBarrierOption>()->GetWithoutChecks(idx));
+  return (T)static_cast<uintptr_t>(static_cast<uint32_t>(
+      AsIntArray<kVerifyFlags, kReadBarrierOption>()->GetWithoutChecks(idx)));
 }
 
 template<bool kTransactionActive, bool kUnchecked>