Bug 1223941 - Enabling C++ APZ in Fennec causes off by one error in placeholder-6.html. r=kats

Update the fuzz test for reftest placeholder-6.html to allow a single pixel to be
off by one in Fennec when C++APZ is enabled.

--HG--
extra : commitid : xWf4FNDIQr

layout/reftests/forms/placeholder/reftest.list

@@ -16,7 +16,7 @@
 == placeholder-3.html placeholder-overridden-ref.html
 == placeholder-4.html placeholder-overridden-ref.html
 == placeholder-5.html placeholder-visible-ref.html
-fuzzy-if(winWidget,160,10) fuzzy-if(asyncPan&&!layersGPUAccelerated,146,299) == placeholder-6.html placeholder-overflow-ref.html
+fuzzy-if(winWidget,160,10) fuzzy-if(Android,1,1) fuzzy-if(asyncPan&&!layersGPUAccelerated,146,299) == placeholder-6.html placeholder-overflow-ref.html
 skip-if(B2G||Mulet) == placeholder-6-textarea.html placeholder-overflow-textarea-ref.html # Initial mulet triage: parity with B2G/B2G Desktop
 # needs-focus == placeholder-7.html placeholder-focus-ref.html
 # needs-focus == placeholder-8.html placeholder-focus-ref.html