[AIX] Print printable byte list as quoted string

.byte supports string, so if the whole byte list are printable,
we can actually print the string for readability and LIT tests maintainence.

        .byte 'H,'e,'l,'l,'o,',,' ,'w,'o,'r,'l,'d
->
        .byte "Hello, world"

Reviewed By: hubert.reinterpretcast

Differential Revision: https://reviews.llvm.org/D102814