PR10589: switch to kernel vscnprintf for _stp_{dbug,warn,error} calls in runtime

PR10589: switch to kernel vscnprintf for _stp_{dbug,warn,error} calls in runtime

_stp_vscnprintf is only suitable for calls from the script, with slightly
different conventions (64-bit ints/pointers, extra formatting directives).

* runtime/runtime.h (_stp_{dbug,warn,error}): Add __attribute__ format(printf).
* runtime/io.c (_stp_vlog): Ditto.  Use vscnprintf().
* runtime/sym.c (_stp_module_check): Remove hexdumping (%.*M) of mismatching
  buildids.  Switch to _stp_warn from printk (KERN_WARNING).
* translate.cxx, runtime/unwind.c: Numerous print formatting tweaks.