prevent_leaky_tests = false results in failure

[charleskawczynski]

Unfortunately, we can't yet run with prevent_leaky_tests = false (which could be a decent bit faster) because we occasionally define global constants, which clash with local variables:

Spaces - serial CPU DSS: Error During Test at none:1
  Got exception outside of a @test
  LoadError: cannot declare Main.device constant; it already has a value
  Stacktrace:
    [1] top-level scope
      @ ~/Dropbox/Caltech/work/dev/CliMA/ClimaCore.jl/test/Spaces/ddss1.jl:21
    [2] include(fname::String)
      @ Base.MainInclude ./client.jl:489
...