Fix failing toolbar unit tests

Since switching to use AsyncLayoutInflater to inflate MenuItems
tests were failing by trying to find views before they were inflated.
Shadow AsyncLayoutInflater to inflate synchronously so that
the tests can find views immediately.

Test: Run the robotests
Bug: 151636938
Change-Id: I8aa8f84f1c583abc1591ca6a7181a87b67e3eee5
Merged-In: I8aa8f84f1c583abc1591ca6a7181a87b67e3eee5
2 files changed