[flang] [llvm] [flang-rt] Add implementation for date_and_time on Windows (PR #190174)

[Michael Kruse via llvm-commits]

https://github.com/Meinersbur commented:

Why use `GetSystemTimePreciseAsFileTime` instead of `GetSystemTimeAsFileTime`?

Linux `gettimeofday` is also only updated every ervery tick, which corresponds to `GetSystemTimeAsFileTime`.

https://github.com/llvm/llvm-project/pull/190174