libstdc++: Make more internal headers include their own dependencies

libstdc++: Make more internal headers include their own dependencies

This adds required headers to a few internal headers that currently
assume their deps will be included first. It's more robust to make them
include their own dependencies, so that later refactoring or reuse of
those headers in new contexts doesn't break.

libstdc++-v3/ChangeLog:

	* include/bits/stl_algo.h: Include <bits/stl_algobase.h>.
	* include/bits/stl_tempbuf.h: Include headers for __try and
	__catch macros, std::pair, and __gnu_cxx::__numeric_traits.
	* include/bits/stream_iterator.h: Include <iosfwd> and headers
	for std::addressof and std::iterator.
	* include/bits/streambuf_iterator.h: Include header for
	std::iterator.
	* include/std/iterator: Do not include <iosfwd>.