Add undo/redo smoke tests for annotations (#1175)

* Add undo/redo tests for annotations

Fixes https://github.com/chanzuckerberg/cellxgene/issues/969

... also refactor the tests for DRY.

* Add done()

* Make e2e annotations tests safer to concurrency

* Add data-testclass for save state.

* Simplify tests and make them dependent on save state

client/src/components/menubar/undoRedoReset.js

@@ -29,6 +29,7 @@ function InformationMenu(props) {
           style={{
             cursor: "pointer"
           }}
+          data-testid="undo"
         />
       </Tooltip>
       <Tooltip
@@ -46,6 +47,7 @@ function InformationMenu(props) {
           style={{
             cursor: "pointer"
           }}
+          data-testid="redo"
         />
       </Tooltip>
       <Tooltip