We're not instantiating `__hash_value_type` anymore, so we don't need
any special handling of it here.

Before this patch, we were dereferencing pointers to objects which were
never constructed. Now we always assume that nodes store `pair<const
KeyT, ValueT>` for maps instead, as they actually do. This patch also
allows for significant follow-up simplifications, since
`__node_value_type` and `__container_value_type` are the same type now.

The need for `_LIBCPP_TEMPLATE_VIS` has been removed in #133233.

This significantly reduces the amount of debug information generated
for codebases using libc++, without hurting the debugging experience.

This also adds a few tests that were missing.

This patch runs clang-format on all of libcxx/include and libcxx/src, in
accordance with the RFC discussed at [1]. Follow-up patches will format
the benchmarks, the test suite and remaining parts of the code. I'm
splitting this one into its own patch so the diff is a bit easier to
review.

This patch was generated with:

   find libcxx/include libcxx/src -type f \
      | grep -v 'module.modulemap.in' \
      | grep -v 'CMakeLists.txt' \
      | grep -v 'README.txt' \
      | grep -v 'libcxx.imp' \
      | grep -v '__config_site.in' \
      | xargs clang-format -i

A Git merge driver is available in libcxx/utils/clang-format-merge-driver.sh
to help resolve merge and rebase issues across these formatting changes.

[1]: https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all

As part of the upcoming clang-formatting of libc++, this patch performs
the long desired removal of the _VSTD macro.

See https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.

In preparation for running clang-format on the whole code base, we are
also removing mentions of the legacy _LIBCPP_INLINE_VISIBILITY macro in
favor of the newer _LIBCPP_HIDE_FROM_ABI.

We're still leaving the definition of _LIBCPP_INLINE_VISIBILITY to avoid
creating needless breakage in case some older patches are checked-in
with mentions of the old macro. After we branch for LLVM 18, we can do
another pass to clean up remaining uses of the macro that might have
gotten introduced by mistake (if any) and remove the macro itself at the
same time. This is just a minor convenience to smooth out the transition
as much as possible.

See
https://discourse.llvm.org/t/rfc-clang-formatting-all-of-libc-once-and-for-all
for the clang-format proposal.

This patch removes undefined behavior in list and forward_list and __hash_table
caused by improperly beginning and ending the lifetime of the various node
classes. It allows removing the _LIBCPP_STANDALONE_DEBUG macro from
these node types since we now properly begin and end their lifetime,
meaning that we won't trip up constructor homing.

See https://reviews.llvm.org/D98750 for more information on what prompted
this patch.

This commit re-applies 0687e4d9f310, which had been reverted in b935882bdce7
because it broke the LLDB build. LLDB folks tell me I can go ahead and
re-commit this now.

Differential Revision: https://reviews.llvm.org/D101206

Co-authored-by: Amy Kwan <amy.kwan1@ibm.com>

This reverts commit 0687e4d9f310249a45c3799ec66aeeeb0efda9f7.
Causes LLDB failures: https://reviews.llvm.org/D101206#4653253