Replace SkFAIL with SK_ABORT.

Test: refactoring CL. Existing unit tests still pass.
Change-Id: I3744b0a27bfc8a2ee6e06d6925ae360d4a2447c5
diff --git a/libs/hwui/SkiaCanvasProxy.cpp b/libs/hwui/SkiaCanvasProxy.cpp
index 16a19ca..81fd4de 100644
--- a/libs/hwui/SkiaCanvasProxy.cpp
+++ b/libs/hwui/SkiaCanvasProxy.cpp
@@ -452,7 +452,7 @@
              break;
          }
          default:
-             SkFAIL("unhandled positioning mode");
+             SK_ABORT("unhandled positioning mode");
          }
      }
 }