libstdc++: Fix failures in new std::complex test [PR119144]

This test fails due to duplicate explicit instantiations on targets
where size_t and unsigned int are the same type. It also fails with
-D_GLIBCXX_USE_CXX11_ABI=0 due to using std::string in constexpr
functions, and with --disable-libstdcxx-pch due to not including
<algorithm> for ranges::fold_left.

libstdc++-v3/ChangeLog:

	PR libstdc++/119144
	* testsuite/26_numerics/complex/tuple_like.cc: Include
	<algorithm>, replace std::string with std::string_view,
	instantiate tests for long instead of size_t.