[BOLT] Do not overwrite starting address in non-relocation mode.

Summary:
In non-relocation mode we shouldn't attemtp to change ELF
entry point.

What made matters worse - it broke '-max-funcs=' and '-funcs=' options
since an entry function more often than not was excluded from the list
of processed functions, and we were setting entry point to 0.

(cherry picked from FBD4720044)