Many existing tests use a Proxy to test the order of observable operations
on a property bag argument that gets passed in to a Temporal API. I am
going to write several more tests that do this, as well. This seems like a
good thing to put into TemporalHelpers, where it can be implemented
consistently so that we don't get discrepancies in which operations are
tracked. (For example, we had some tests which didn't test for an ownKeys
operation that was supposed to be there.)
Updates existing tests to use this helper.