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/tests/PathOpsQuadLineIntersectionThreadedTest.cpp b/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
index 7e33b7b..a4f87df 100644
--- a/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
+++ b/tests/PathOpsQuadLineIntersectionThreadedTest.cpp
@@ -91,7 +91,7 @@
         SkDPoint xy = quad.ptAtT(tIndex / 4.0);
         for (int h = -2; h <= 2; ++h) {
             for (int v = -2; v <= 2; ++v) {
-                if (h == v && abs(h) != 1) {
+                if (h == v && SkTAbs(h) != 1) {
                     continue;
                 }
                 double x = xy.fX;