When we ship LLVM 16, <ranges> won't be considered experimental anymore.
We might as well do this sooner rather than later.
Differential Revision: https://reviews.llvm.org/D132151
All supported compilers that support C++20 now support concepts. So, remove
`_LIB_LIBCPP_HAS_NO_CONCEPTS` in favor of `_LIBCPP_STD_VER > 17`. Similarly in
the tests, remove `// UNSUPPORTED: libcpp-no-concepts`.
Differential Revision: https://reviews.llvm.org/D121528
The unique (ha!) thing about this range type is that it's move-only.
Its contiguity is unsurprising (most of our test ranges are contiguous).
Discussed in D111231 but committed separately for clarity.
Since we officially don't support several older compilers now, we can
drop a lot of the markup in the test suite. This helps keep the test
suite simple and makes sure that UNSUPPORTED annotations don't rot.
This is the first patch of a series that will remove annotations for
compilers that are now unsupported.
Differential Revision: https://reviews.llvm.org/D107787
Louis Dionne