Also standardize the license comment in several files where it was
different from what we normally do.

The `parse.pass.cpp` tests doen't need to call
`test_format_context_create` to create a `basic_format_context`, so they
shouldn't include `test_format_context.h`.

The `to_address` mechanism works around the iterator debugging
mechanisms of MSVC STL. Related to
[LWG3989](https://cplusplus.github.io/LWG/issue3989).

Discovered when implementing `formatter<tuple>` in MSVC STL. With the
inclusion removed, `std/utilities/format/format.tuple/parse.pass.cpp`
when using enhanced MSVC STL (and `/utf-8` option for MSVC).

Some tests in our test suite are unbelievably slow on GCC due to the
use of the always_inline attribute. See [1] for more details.

This patch introduces the GCC-ALWAYS_INLINE-FIXME lit feature to
disable tests that are plagued by that issue. At the same time, it
moves several existing tests from ad-hoc `UNSUPPORTED: gcc-12` markup
to the new GCC-ALWAYS_INLINE-FIXME feature, and marks the slowest tests
reported by the CI as `UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME`.

[1]: https://discourse.llvm.org/t/rfc-stop-supporting-extern-instantiations-with-gcc/71277/1

Differential Revision: https://reviews.llvm.org/D152736

The code has been quite ready for a while now and there are no more ABI
breaking papers. So this is a good time to mark the feature as stable.

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D150802

This is based on the last open review comment in D144331 and is applied
to all occurrences.

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D147885

std::format is currently experimental, so there is technically no
deployment target requirement for it (since the only symbols required
for it are in `libc++experimental.a`).

However, some parts of std::format depend indirectly on the floating
point std::to_chars implementation, which does have deployment target
requirements.

This patch removes all the availability format for std::format and
updates the XFAILs in the tests to properly explain why they fail
on old deployment targets, when they do. It also changes a couple
of tests to avoid depending on floating-point std::to_chars when
it isn't fundamental to the test.

Finally, some tests are marked as XFAIL but I added a comment saying

   TODO FMT This test should not require std::to_chars(floating-point)

These tests do not fundamentally depend on floating-point std::to_chars,
however they end up failing because calling std::format even without a
floating-point argument to format will end up requiring floating-point
std::to_chars. I believe this is an implementation artifact that could
be avoided in all cases where we know the format string at compile-time.
In the tests, I added the TODO comment only to the places where we could
do better and actually avoid relying on floating-point std::to_chars
because we know the format string at compile-time.

Differential Revision: https://reviews.llvm.org/D134598

Implements the range-default-formatter specialization range_format::map.

Implements parts of
- P2286R8 Formatting Ranges
- P2585R0 Improving default container formatting

Depends on D140653

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D140801

Implements parts of
- P2286R8 Formatting Ranges

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D136775