Unit Test memory cleanup

This is a first pass at fixing #4185. @jasonsanjose 

I updated all tests that use `SpecRunnerUtils.createTestWindowAndRun()` and tried to release all references to the test window and anything inside it so it will get released on call to `SpecRunnerUtils.closeTestWindow()`

On my Window 7 system, when running Integration Tests this reduces memory ~100M (~11%).

We should do a similar analysis of the other `SpecRunnerUtils` methods:

```
createMockDocument;
createMockActiveDocument;
createMockElement;
createMockEditorForDocument;
createMockEditor;
loadProjectInTestWindow;
openProjectFiles;
createTextFile;
```