posix: glob, glob64 should not be declared __THROW [BZ #27522]

These functions invoke callbacks with GLOB_ALTDIRFUNC, so they
are not leaf functions (as implied by _THROW).  Use __THROWNL
and __REDIRECT_NTHNL to express this.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>