More 1.12 compat

[Keno]

With this and the LCU fixes, Revise should pass tests again on 1.12.

[Keno]

Updated to bump LCU and cherry-pick the additional fixes from #829

[KristofferC]

Interesting that the linux testers don't know about LCU 3.0.1.

[Keno]

Probably just hadn't propagated yet. Rerunning.

[Keno]

@timholy The last issue here is that ExponentialUtilities v1.9.0 is not compatible with all the julia versions we want to test. Can we switch this test to be more self contained and include some minimal in the test code itself rather than depending on some external package?

[Keno]

That's mostly a separate change though. I would propose merging this first and then addressing that last issue.

[timholy]

Can we switch this test to be more self contained and include some minimal in the test code itself rather than depending on some external package?

Yes, that needs to happen. I have been doing that for newer tests, but I haven't migrated old tests. Doesn't need to stand in the way of this PR.