The ldbl-opt version of w_scalbln.c is not in fact needed; it handles
compat symbol versions for libc, but this file isn't built for libc,
only for libm. This patch removes this file.
Tested with build-many-glibcs.py that installed stripped shared
libraries are unchanged by this patch.
* sysdeps/ieee754/ldbl-opt/w_scalbln.c: Remove file.