[perl #117355] very basic tests for [ul]c(first)? under use bytes

the [lu]cfirst tests are TODO due to #117355
XXX Patch for discussion: [perl #117355] [lu]cfirst don't respect 'use bytes'
[perl #117355] unTODO the [lu]cfirst under bytes tests
[perl #117355] [lu]cfirst don't respect 'use bytes'