shortcut_test.js: Preset has changed

This test was failing since !123 (see eed71f5d) but we didn't see it because of #2899.

browser/test/QUnit/testFiles/shortcut_test.js

@@ -28,7 +28,7 @@ QUnit.test("shortcuts on scatterplot", function(assert) {
 
     assert.equal(sp.splitX, sp.AXIS_GENE_V)
     shortcut.checkKey(keyMock({'keyCode': 52})) // Preset 4
-    assert.equal(sp.splitX, 'consensusLength')
+    assert.equal(sp.splitX, 'averageLength')
 
     assert.equal(shortcut.system_shortcuts[76][0], "IGL", "System shortcut for IGL")
     assert.equal(m.system_selected.length, 2, "We have 2 systems, TRG and IGH")