Correct sub-hairline tessellation threshold

Change-Id: Id868d41a36db5b4daa762d84b6329f9c31916bce
diff --git a/libs/hwui/PathTessellator.cpp b/libs/hwui/PathTessellator.cpp
index 69ccdfa..395bbf6 100644
--- a/libs/hwui/PathTessellator.cpp
+++ b/libs/hwui/PathTessellator.cpp
@@ -109,7 +109,7 @@
         }
 
         if (isAA && halfStrokeWidth != 0 && inverseScaleX == inverseScaleY &&
-                halfStrokeWidth * inverseScaleX < 0.5f) {
+                2 * halfStrokeWidth < inverseScaleX) {
             maxAlpha *= (2 * halfStrokeWidth) / inverseScaleX;
             halfStrokeWidth = 0.0f;
         }