confstr/confstr01.c: cleanup

cleanup the confstr01.c test case.

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
confstr/confstr01.c: add new names

Add new case for confstr(2) :
_CS_GNU_LIBC_VERSION
_CS_GNU_LIBPTHREAD_VERSION

Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>