For annotation test no log ax or ay is pixel

Don't take the log of the given test values if ax or ay is pixel.

Author: nicholas-esterer

src/plots/cartesian/axes.js

@@ -117,6 +117,7 @@ axes.coerceRef = function(containerIn, containerOut, gd, attr, dflt, extraOption
 axes.getRefType = function(ar) {
     if(ar === undefined) { return ar; }
     if(ar === 'paper') { return 'paper'; }
+    if(ar === 'pixel') { return 'pixel'; }
     if(/( domain)$/.test(ar)) { return 'domain'; } else { return 'range'; }
 };