Add support for %x, %lx and %zx to _dl_exception_create_format and pad
to the full width with 0.
* elf/Makefile (tests-internal): Add tst-create_format1.
* elf/dl-exception.c (_dl_exception_create_format): Support
%x, %lx and %zx.
* elf/tst-create_format1.c: New file.
This commit separates allocating and raising exceptions. This
simplifies catching and re-raising them because it is no longer
necessary to make a temporary, on-stack copy of the exception message.
