[DevTools] enable async stacks by default

third_party/WebKit/LayoutTests/http/tests/inspector/debugger-test.js

 function scheduleTestFunction()
 {
     setTimeout(testFunction, 0);
 }
 
 var initialize_DebuggerTest = function() {
 
 InspectorTest.preloadPanel("sources");
 
 InspectorTest.startDebuggerTest = function(callback, quiet)
@@ skipping 86 matching lines @@
 InspectorTest.runTestFunctionAndWaitUntilPausedPromise = function()
 {
     var cb;
     var p = new Promise(fullfill => cb = fullfill);
     InspectorTest.runTestFunctionAndWaitUntilPaused(cb);
     return p;
 }
 
 InspectorTest.runAsyncCallStacksTest = function(totalDebuggerStatements, maxAsyncCallStackDepth)
 {
-    var defaultMaxAsyncCallStackDepth = 8;
+    var defaultMaxAsyncCallStackDepth = 32;
 
     InspectorTest.setQuiet(true);
     InspectorTest.startDebuggerTest(step1);
 
     function step1()
     {
         InspectorTest.DebuggerAgent.setAsyncCallStackDepth(maxAsyncCallStackDepth || defaultMaxAsyncCallStackDepth, step2);
     }
 
     function step2()
@@ skipping 607 matching lines @@
     var bookmark = bookmarks[index];
     if (bookmark) {
         bookmark[Sources.JavaScriptSourceFrame.BreakpointDecoration._elementSymbolForTest].click();
     } else {
         InspectorTest.addResult(`Could not click on Javascript breakpoint - lineNumber: ${lineNumber}, index: ${index}`);
         next();
     }
 }
 
 };