Make dump.c nul-and-UTF8 clean
Devel::Peek: Test that we dump CvOUTSIDE properly
sv_peek didn't add quotes before, doesn't need them now
dump.c, sv_dump: Escape the name of the OUTSIDE sub
Fixups for ext/Devel-Peek/t/Peek.t
ext/Devel-Peek/t/Peek.t: Don't leave PATH tainted.

The tests originally left $ENV{PATH} tainted.  However, now that
the file ends up using fresh_perl_is(), $ENV{PATH} may end up
being used in some systems, like in Windows.