Update audit.js and fix error catching logic in should().throw()

Fetch/update audit.js in non-WPT layout tests and also fix the error
in the error catching logic in should().throw() assertion.

The updated code checks if the |error| object passed by try/catch
is "DOMException". This is unnecessarily specific, so this CL changes
the check to look for the "Error" type, which is more generic.

Bug: 865614
Test: All layout tests pass.
Change-Id: I16acacb26c194a0ff950aca05e931195bf55167f

webaudio/resources/audit.js

@@ -314,7 +314,7 @@ window.Audit = (function() {
           didThrowCorrectly = true;
           passDetail = '${actual} threw ' + error.name + errorMessage + '.';
         } else if (typeof(this._expected) == "string" &&
-                   error instanceof DOMException &&
+                   error instanceof Error &&
                    error.name === this._expected) {
           // A DOMException was thrown and expected, and the names match
           didThrowCorrectly = true;