qunit: Remove redundant conditional for sandbox teardown

Follows-up 0a20891, which added support for the `executeNow` parameter to QUnit.module. To properly support nested modules, we also need to skip registering a second setup and teardown because nested modules already run the beforeEach (setup), and afterEach (teardown), of their parent modules. During setup this would needlessly create two sandboxes and override the 'sandbox' property on the same 'this' context object. During teardown it would fail because the inner module's teardown would have already torn down the sandbox. Change-Id: Ib17bbbef45b2bd0247979cf0fa8aed17800c54a0

Author: Krinkle

tests/qunit/data/testrunner.js

@@ -64,6 +64,12 @@
 var orgModule = QUnit.module;
 
 QUnit.module = function ( name, localEnv, executeNow ) {
+if ( QUnit.config.moduleStack.length ) {
+// When inside a nested module, don't add our Sinon
+// setup/teardown a second time.
+return orgModule.apply( this, arguments );
+}
+
 if ( arguments.length === 2 && typeof localEnv === 'function' ) {
 executeNow = localEnv;
 localEnv = undefined;
@@ -85,9 +91,7 @@
 localEnv.teardown.call( this );
 }
 
-if ( this.sandbox ) {
-this.sandbox.verifyAndRestore();
-}
+this.sandbox.verifyAndRestore();
 }
 }, executeNow );
 };