STL.natvis: Add alternative type name for time_point

[Nerixyz]

clang-cl will produce

std::chrono::time_point<std::chrono::system_clock,std::chrono::duration<long long,std::ratio<1,10000000>>>

as the type name for std::chrono::system_clock::time_point whereas MSVC will produce

std::chrono::time_point<std::chrono::system_clock,std::chrono::duration<__int64,std::ratio<1,10000000>>>

Notice: long long vs __int64 (llvm/llvm-project#134156).

As a workaround, I added the type from clang-cl as an <AlternativeType>.

[StephanTLavavej]

I'm mirroring this to the MSVC-internal repo - please notify me if any further changes are pushed.

[StephanTLavavej]

Thanks for helping to support Clang as a first-class citizen! 🎉 🐱 🐈

I triple-mirrored this change to VS so it will take effect, internal VS-PR-627142.