Bug 1308436 - Update devtools tests with another Web Audio API call the throws the right exception. r=karlt

Differential Revision: https://phabricator.services.mozilla.com/D4104

--HG--
extra : rebase_source : 1b0bdbf5416b560a46a755348eada4bedab6fd18
extra : histedit_source : c15ee4e5bb5f2b0af88ace7881729a8a6350fe57

devtools/client/webaudioeditor/test/doc_bug_1112378.html

@@ -14,7 +14,7 @@
       "use strict";
 
       const ctx = new AudioContext();
-      const osc = ctx.createOscillator();
+      const osc = ctx.createStereoPanner();
 
       function throwError() {
         try {
@@ -34,7 +34,7 @@
 
       function throwDOMException() {
         try {
-          osc.frequency.setValueAtTime(0, -1);
+          osc.channelCount = 3;
         } catch (e) {
           return {
             lineNumber: e.lineNumber,