TODO test for 120535
Add UTF8 flag to keys returned by B::HV->ARRAY

hv_iternextsv() ignores the HEK flags, but we do care about the UTF8 flag
at least when returning hash keys from B::HV->ARRAY
un-TODO the test for 120535, Reini's patch fixes it
[perl #120535] Add UTF8 flag to B::HV->ARRAY keys