Reland "Prepare blink to unify definitions of load completion"

LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html

Index: LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html
diff --git a/LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html b/LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html
index 1fb2be280a4f1f0920fed0913dd945037c11de84..ab0bc0c31e97ff7cb205bb45978cc0842929fa89 100644
--- a/LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html
+++ b/LayoutTests/webaudio/scriptprocessornode-upmix2-8channel-input.html
@@ -21,14 +21,11 @@ var sourceChannels = 2;
 var inputChannels = 8;
 var outputChannels = 6;
 
+window.jsTestIsAsync = true;
+
 function runTest() {
-    if (window.testRunner) {
+    if (window.testRunner)
         testRunner.dumpAsText();
-        testRunner.waitUntilDone();
-    }
-
-    window.jsTestIsAsync = true;
-
     runJSNodeTest();
 }