fix: create a window capturer correctly (#13689)

* fix: create a window capturer correctly

We were incorrectly creating two screen capturers instead of a window
capturer

* spec: ensure dc tests pass

* spec: enable all tests after verifying dc tests work

spec/api-desktop-capturer-spec.js

@@ -69,7 +69,11 @@ describe('desktopCapturer', () => {
       return done()
     }
 
+    const { BrowserWindow } = remote
+    const w = new BrowserWindow({ width: 200, height: 200 })
+
     desktopCapturer.getSources({types: ['window']}, (error, sources) => {
+      w.destroy()
       expect(error).to.be.null()
       expect(sources).to.be.an('array').that.is.not.empty()
       for (const {display_id: displayId} of sources) {