libstdc++: Fix non-reserved names in headers

libstdc++: Fix non-reserved names in headers

My recent changes to std::exception_ptr moved some members to be inline
in the header but didn't replace the variable names with reserved names.

The "tmp" variable must be fixed. The "other" parameter is actually a
reserved name because of std::allocator<T>::rebind<U>::other but should
be fixed anyway.

There are also some bad uses of "ForwardIterator" in <ranges>.

There's also a "il" parameter in a std::seed_seq constructor in <random>
which is only reserved since C++14.

libstdc++-v3/ChangeLog:

	* include/bits/random.h (seed_seq(initializer_list<T>)): Rename
	parameter to use reserved name.
	* include/bits/ranges_algo.h (shift_left, shift_right): Rename
	template parameters to use reserved name.
	* libsupc++/exception_ptr.h (exception_ptr): Likewise for
	parameters and local variables.
	* testsuite/17_intro/names.cc: Check "il". Do not check "d" and
	"y" in C++20 mode.