Add REQUIRE upgrade tests to CI

The original upgrade tests were disabled by default for being too slow. They're
too slow because they test with a wide range of previous ASDF versions.

Add new tests that run only if the full upgrade test suite is not run. These
test upgrading only from the implementation provided ASDF. This is much faster
because than testing every old version. Plus, it matches the real world upgrade
conditions for the vast majority of users.

This catches #72.
17 jobs for !178 with require-upgrade-tests in 62 minutes and 1 second (queued for 34 minutes)
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