Bug 656167 - Disable reftest until fixed layers are re-enabled (test-only).

layout/reftests/reftest-sanity/reftest.list

@@ -91,7 +91,8 @@ fails-if(!browserIsRemote) == test-displayport.html test-displayport-ref.html #
 skip-if(!browserIsRemote) != test-displayport-2.html test-displayport-ref.html # bug 593168
 
 # IPC Position-fixed frames/layers test
-== test-pos-fixed.html test-pos-fixed-ref.html
+# Fixed layers are temporarily disabled (bug 656167).
+#== test-pos-fixed.html test-pos-fixed-ref.html
 
 # reftest syntax: require-or
 require-or(unrecognizedCondition,skip) script scripttest-fail.html