Remove include of stdlib.h from SkTypes.h.

Unfortunately, immintrin.h (which is also included by SkTypes)
includes xmmintrin.h which includes mm_malloc.h which includes
stdlib.h for malloc even though, from the implementation, it is
difficult to see why.

Fortunately, arm_neon.h does not seem to be involved in such
shenanigans, so building for Android will keep things sane.

TBR=reed@google.com
Doesn't change Skia API, just moves an include.

Review URL: https://codereview.chromium.org/1313203003
diff --git a/src/core/SkResourceCache.cpp b/src/core/SkResourceCache.cpp
index 70dc8f9..922fc7e 100644
--- a/src/core/SkResourceCache.cpp
+++ b/src/core/SkResourceCache.cpp
@@ -13,6 +13,7 @@
 #include "SkResourceCache.h"
 
 #include <stddef.h>
+#include <stdlib.h>
 
 DECLARE_SKMESSAGEBUS_MESSAGE(SkResourceCache::PurgeSharedIDMessage)