Remove describe('readFeatures') in GPX tests

Just a remove an unnecessary level of nesting. No functional change.

test/spec/ol/format/gpxformat.test.js

@@ -19,8 +19,6 @@ describe('ol.format.GPX', function() {
     });
   });
 
-  describe('readFeatures', function() {
-
   describe('rte', function() {
 
     it('can read an empty rte', function() {
@@ -561,8 +559,6 @@ describe('ol.format.GPX', function() {
 
 });
 
-});
-
 
 goog.require('ol.Feature');
 goog.require('ol.format.GPX');