fix: don't crash on tray.setContextMenu(null) (#14331)

spec/api-tray-spec.js

@@ -0,0 +1,25 @@
+const {remote} = require('electron')
+const {Menu, Tray, nativeImage} = remote
+
+describe('tray module', () => {
+  describe('tray.setContextMenu', () => {
+    let tray
+
+    beforeEach(() => {
+      tray = new Tray(nativeImage.createEmpty())
+    })
+
+    afterEach(() => {
+      tray.destroy()
+      tray = null
+    })
+
+    it('accepts menu instance', () => {
+      tray.setContextMenu(new Menu())
+    })
+
+    it('accepts null', () => {
+      tray.setContextMenu(null)
+    })
+  })
+})