Remove all usage of fmin and fmax

bug:22208220

Removes needless call, and upconversion to doubles in multiple places.

Change-Id: I1b949fa5f206446ac34de800154c0147d6bd8034
diff --git a/libs/hwui/TessellationCache.cpp b/libs/hwui/TessellationCache.cpp
index 9df1f0d..17cb3a7 100644
--- a/libs/hwui/TessellationCache.cpp
+++ b/libs/hwui/TessellationCache.cpp
@@ -244,8 +244,8 @@
         const Vertex& point2d = casterVertices2d[i];
         casterPolygon[i] = (Vector3){point2d.x, point2d.y, 0};
         mapPointFakeZ(casterPolygon[i], casterTransformXY, casterTransformZ);
-        minZ = fmin(minZ, casterPolygon[i].z);
-        maxZ = fmax(maxZ, casterPolygon[i].z);
+        minZ = std::min(minZ, casterPolygon[i].z);
+        maxZ = std::max(maxZ, casterPolygon[i].z);
     }
 
     // map the centroid of the caster into 3d