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/pathops/SkPathOpsTypes.cpp b/src/pathops/SkPathOpsTypes.cpp
index c3de93a..bf43c14 100644
--- a/src/pathops/SkPathOpsTypes.cpp
+++ b/src/pathops/SkPathOpsTypes.cpp
@@ -160,7 +160,7 @@
         return a == b ? 0 : SK_MaxS32;
     }
     // Find the difference in ULPs.
-    return abs(floatIntA.fSignBitInt - floatIntB.fSignBitInt);
+    return SkTAbs(floatIntA.fSignBitInt - floatIntB.fSignBitInt);
 }
 
 // cube root approximation using bit hack for 64-bit float