Get the LocalTests running in CI again

[zadjii-msft]

We created LocalTests_TerminalApp as a way to separate out the tests that couldn't be run in CI.

Originally, it's because we didn't have Xaml Islands in CI, so they wouldn't work there. Then, we were able to remove the unittest's dependency on XAML Islands (#3833). However, the tests still don't work in CI, because they require the Microsoft.VCLibs.140.00.Debug framework package, which isn't deployed by default on our CI machines.

An upcoming TAEF release will let us deploy the package from our test's folder, but we need to wait for an updated TAEF for that. This task represents looping back on that thread to get the updated TAEF and configure the tests to run in CI again. Then we can get rid of the LocalTests project, and just have one set of unittests for the TerminalApp.

[zadjii-msft]

With #4105 merging soon, we're updated to a version of TAEF that'll work for installing framework packages automatically. However, I need to find the right way to get

the dependency AppX next to TE.exe or next to the test

so that TAEF can install it. Should that be in it's own nuget that we have the CI build pull down? Should we just ship it in our dep/ directory, and have the TestHostApp copy it over to it's output path?

This issue is now tracking just that work.