t/flip.t fails under perl 5.18 due to hash ordering assumptions

[chuckadams]

Test output below. I'd make a pull request, but I'm a bit pressed for time and the fix is pretty obvious: simply remove the duplicate values from the test hash, since there's no deterministic result you'll get from flipping such hashes as long as key order is randomized.

t/flip.t ..................... 1/? 
#   Failed test at t/flip.t line 12.
#     Structures begin differing at:
#          $got->{bar} = '2'
#     $expected->{bar} = '3'

#   Failed test 'Returns hash in list context'
#   at t/flip.t line 16.
#     Structures begin differing at:
#          $got->{bar} = '2'
#     $expected->{bar} = '3'
# Looks like you failed 2 tests of 3.
t/flip.t ..................... Dubious, test returned 2 (wstat 512, 0x200)

[schwern]

Fixed by #262