As a whole, this is best reviewed by ignoring whitespace. I've also arranged it as a series of well-structured commits.

🧰 Toolset update

• New pool: VS 2022 17.3 Preview 3, Clang 14, July 2022's Patch Tuesday.
• README.md: Mention 17.3 Preview 3.
• Require Clang 14 and MSVC 19.33.
  • The internal build now uses MSVC 19.33.

🚀 Clang 14 coroutines

• Remove workarounds now that Clang 14 supports coroutines.
  • Fixes Clang and EDG support for <coroutine> #1223 by enabling <coroutine> test coverage for Clang.
• Unskip libcxx tests that are passing with Clang 14 (mostly coroutines).
• Silence a valid but innocuous Clang warning in P0912R5_coroutine.
• Work around LLVM-56507 "clang 14.0.5 i686-pc-windows-msvc <coroutine> ICE: failed to perform tail call elimination on a call site marked musttail".

🩹 Workaround removals

• Remove workaround for VSO-1543660 "Standard Library Header Units: <expected> ICEs with Assertion failed: IsInClassDefn()"
• Remove workarounds now that Clang 14 supports _MSVC_EXECUTION_CHARACTER_SET.
• Remove workaround for VSO-522105 "REPORTED: __STDCPP_DEFAULT_NEW_ALIGNMENT__ should have size_t type", resolved on 2018-01-02.
• Remove workaround now that we've implemented P2231R1 Completing constexpr In optional And variant (P2231 Completing constexpr in optional and variant #2005).
• Remove workaround for DevCom-1656924 "EDG works wrong with constinit", fixed in 17.2.
• Remove workaround now that we've implemented P1023R0 constexpr For std::array Comparisons (constexpr for std::array Comparisons #599).
• Remove not_ranges_destroy() workarounds now that we've implemented ranges::destroy (Minimal changes to support constexpr allocation in MSVC #1313).
• Remove TRANSITION, VSO-1172852 ("Coroutine not at final suspend point after throwing from unhandled_exception") in <experimental/generator> as this is permanent.
• Remove workaround for VSO-801237 "Issue calling WideCharToMultiByte from _Wcrtomb with CP_UTF8", as our tests now assume modern OSes.
  • Adjust the locale name to "en-US.UTF-8", for consistency with other tests.
  • If an exception is thrown, the message is no longer a warning - the test will fail.
• Partially remove workarounds for VSO-934264 "Explicitly-defaulted inherited default constructor is not correctly implicitly constexpr".
  • This bug is still active.
  • Perma-workaround: Mark the lambdas as constexpr, for consistency with other lambdas here.

📄 clang-format 14

• Update clang-format 14 defaults, no customizations.
• Reformatting commits:
  • clang-format aligning = default/= delete, no manual changes.
  • clang-format adding spaces to rvalue references to arrays/functions, all good, no manual changes.
  • clang-format removing spurious spaces in requires reference parameters, all good, no manual changes.
  • clang-format removing spurious spaces in an assignment operator, all good, no manual changes.
  • clang-format adjusting indentation, good/neutral, no manual changes.
  • clang-format adjusting indentation, needs manual wrapping to avoid exceeding 120.
  • clang-format removing spaces, weird but not worth adjusting, no manual changes.
  • clang-format adding spaces, weird but not worth adjusting, no manual changes.