Fix use of intrinsics on windows ARM platforms

[mborland]

Closes: #926
Closes: #927

Changes use of intrinsics: https://learn.microsoft.com/en-us/cpp/intrinsics/umul128?view=msvc-170 and https://learn.microsoft.com/en-us/cpp/intrinsics/emul-emulu?view=msvc-170

[codecov]

Codecov Report

Merging #928 (0c1b469) into develop (e084a29) will not change coverage.
The diff coverage is n/a.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop     #928   +/-   ##
========================================
  Coverage    92.95%   92.95%           
========================================
  Files           85       85           
  Lines         8047     8047           
========================================
  Hits          7480     7480           
  Misses         567      567           

Files Changed	Coverage Δ
.../boost/json/detail/charconv/detail/emulated128.hpp	0.00% <ø> (ø)

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[cppalliance-bot]

Benchmark test results. More info at https://benchmark.cppalliance.org/jsonbenchmarks-pullrequests/928/pullrequest.html

[cppalliance-bot]

Benchmark test results. More info at https://benchmark.cppalliance.org/jsonbenchmarks-pullrequests/928/pullrequest.html

[grisumbras]

I feel like rather than doing if defined(BOOST_JSON_HAS_MSVC_64BIT_INTRINSICS) && !defined(_M_ARM64) and similar, we should have BOOST_JSON_HAS_MSVC_X86_64_INTRINSICS, BOOST_JSON_HAS_MSVC_ARM64_INTRINSICS BOOST_JSON_HAS_MSVC_X86_INTRINSICS, BOOST_JSON_HAS_MSVC_ARM32_INTRINSICS. Or does the overlap make it impractical?

[mborland]

I feel like rather than doing if defined(BOOST_JSON_HAS_MSVC_64BIT_INTRINSICS) && !defined(_M_ARM64) and similar, we should have BOOST_JSON_HAS_MSVC_X86_64_INTRINSICS, BOOST_JSON_HAS_MSVC_ARM64_INTRINSICS BOOST_JSON_HAS_MSVC_X86_INTRINSICS, BOOST_JSON_HAS_MSVC_ARM32_INTRINSICS. Or does the overlap make it impractical?

There is overlap in the 64-bit platforms with __umulh, and the bit scan intrinsics which are the primary ones used. If you want me to change it I can.

[grisumbras]

Nah, let's merge it as-is. I'm expecting to remove it with dependency on Boost.Charconv soon anyway.