Bump up allowed maxAllowedError in webaudio tests.

LayoutTests/webaudio/resources/distance-model-testing.js

 var sampleRate = 44100.0;
 
 // How many panner nodes to create for the test.
 var nodesToCreate = 100;
 
 // Time step when each panner node starts.
 var timeStep = 0.001;
 
 // Make sure we render long enough to get all of our nodes.
 var renderLengthSeconds = timeStep * (nodesToCreate + 1);
@@ skipping 111 matching lines @@
 }
 
 function checkDistanceResult(model) {
     return function(event) {
         renderedBuffer = event.renderedBuffer;
         renderedData = renderedBuffer.getChannelData(0);
 
         // The max allowed error between the actual gain and the expected
         // value.  This is determined experimentally.  Set to 0 to see what
         // the actual errors are.
-        var maxAllowedError = 2.3e-6;
+        var maxAllowedError = 3.3e-6;
    
         var success = true;
 
         // Number of impulses we found in the rendered result.
         var impulseCount = 0;
 
         // Maximum relative error in the gain of the impulses.
         var maxError = 0;
 
         // Array of locations of the impulses that were not at the
@@ skipping 54 matching lines @@
 
         if (success) {
             testPassed("Distance test passed for distance model " + model);
         } else {
             testFailed("Distance test failed for distance model " + model);
         }
 
         finishJSTest();
     }
 }