Undefine SK_DISABLE_ARC_TO_LINE_TO_CHECK and rebaseline layout test

Bug: skia:7794
Change-Id: I49baa57209b4c1a599e84f30d84cbf5282aab7eb
Reviewed-on: https://chromium-review.googlesource.com/1032794Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@chromium.org>
Cr-Commit-Position: refs/heads/master@{#554817}

skia/config/SkUserConfig.h

@@ -234,10 +234,6 @@ SK_API void SkDebugf_FileLine(const char* file, int line, bool fatal,
 #define SK_DONT_OPTIMIZE_SRC_PROFILES_FOR_SPEED
 #define SK_DONT_OPTIMIZE_DST_PROFILES_FOR_SPEED
 
-// Deleting this requires rebaselining trivial diffs to
-// fast/canvas/canvas-composite-transformclip.html
-#define SK_DISABLE_ARC_TO_LINE_TO_CHECK
-
 ///////////////////////// Imported from BUILD.gn and skia_common.gypi
 
 /* In some places Skia can use static initializers for global initialization,