Do not initialize previous store state in "use_store" (#45268)

The "use_store" context manager is used to swap the value
of a global variable (spack.store.STORE), while keeping
another global variable consistent (spack.config.CONFIG).

When doing that it tries to evaluate the previous value
of the store, if that was not done already. This is wrong,
since the configuration might be in an "intermediate" state
that was never meant to trigger side effects.

Remove that operation, and add a unit test to
prevent regressions.

0 files changed, 0 insertions, 0 deletions