Make VSCode test runner happy with loop in storage subsystem tests

[HerbCaudill]

For whatever reason, the VSCode test runner doesn't see tests inside a forEach loop:

Object.entries(adaptersToTest).forEach(([adapterName, adapter]) => {
    describe("Automerge document storage", () => {
      it("stores and retrieves an Automerge document", async () => {
         // ...

but it does if they're in a for ... of loop:

for (const [adapterName, adapter] of Object.entries(adaptersToTest)) {
    describe("Automerge document storage", () => {
      it("stores and retrieves an Automerge document", async () => {
         // ...