This increases the chance to use "short" calls.
Assumptions:
- LLVM preserves the order of functions in a module
- The wrapper function are smaller than the wrapped functions
- The target CPU has "short" PC-relative variation of call/jmp instructions
and they are preferrable over the "long" ones.
A motivation:
- To avoid some relocations for XIP, I want to use xtensa PC-relative
call instructions, which can only reach ~512KB.