testing something that is "wrong" leads to a stacktrace in cro::http::test

[ufobat]

> perl6 -Ilib t/10-Routes.t
    not ok 1 - Status is acceptable
    # Failed test 'Status is acceptable'
    # at site#sources/C22F8134E5F624ED8BC7EAA1FD9E428A90415E53 (Cro::HTTP::Test) line 166
    # expected: '200'
    #      got: '405'
Type check failed in binding to parameter '$got'; expected Cro::MediaType but got Nil (Nil)
  in sub test-media-type at /home/martin/.rakudobrew/moar-2018.08/install/share/perl6/site/sources/C22F8134E5F624ED8BC7EAA1FD9E428A90415E53 (Cro::HTTP::Test) line 273
  in block  at /home/martin/.rakudobrew/moar-2018.08/install/share/perl6/site/sources/C22F8134E5F624ED8BC7EAA1FD9E428A90415E53 (Cro::HTTP::Test) line 177
  in sub subtest at /home/martin/.rakudobrew/moar-2018.08/install/share/perl6/sources/C712FE6969F786C9380D643DF17E85D06868219E (Test) line 415
  in sub subtest at /home/martin/.rakudobrew/moar-2018.08/install/share/perl6/sources/C712FE6969F786C9380D643DF17E85D06868219E (Test) line 405
  in sub test at /home/martin/.rakudobrew/moar-2018.08/install/share/perl6/site/sources/C22F8134E5F624ED8BC7EAA1FD9E428A90415E53 (Cro::HTTP::Test) line 161
  in block <unit> at t/10-Routes.t line 8