llvm-tli-checker: Remove TLINameList helper struct
This avoids subclassing std::vector and a static constructor.
This started as a refactor to make TargetLibraryInfo available during
printing so a custom name could be reported. It turns out this struct
wasn't doing anything, other than providing a hacky way of printing the
standard name instead of the target's custom name. Just remove this and
stop hacking on the TargetLibraryInfo to falsely report the function
is available later.
