libstdc++: Simplify __throw_out_of_range_fmt for freestanding

libstdc++: Simplify __throw_out_of_range_fmt for freestanding

There is no point expanding the format string if we're just going to
abort instead of throw an exception. And for freestanding or non-verbose
builds we shouldn't do it either, to reduce the binary size.

Signed-off-by: Jonathan Wakely <jwakely@redhat.com>
libstdc++-v3/ChangeLog:

	* src/c++11/functexcept.cc (__throw_out_of_range_fmt): Do not
	expand the format string for freestanding, or non-vebose, or if
	we're just going to abort anyway.
	* src/c++11/snprintf_lite.cc: Remove unused header and
	declaration.