Safe: clean up some tests

[mauke]

• BEGIN { require Config; Config->import; } -> use Config;
• new Safe -> Safe->new
• more use of Test::More skip_all instead of manual print/exit

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• This set of changes does not require a perldelta entry.

[jkeenan]

This looks good but the fact that different changes are being made in different files makes me think I'm at risk of missing something. So additional eyeballs requested.

[mauke]

Good point. I fixed the condition in t/safenamedcap.t.

[tonycoz]

This should bump $Safe::VERSION, otherwise it's good.

[mauke]

Done.