Fix std::chrono/date conflict for mac builds with C++20

[skottmckay]

Description

Fix usage of c++ std::chrono::operator<< in mac builds for wider range of xcode/targets.

Motivation and Context

Resolve #21033

[snnn]

We may also consider using absl::date, then we can totally get rid of the third-party date library, regardless C++ standard version.
For example:

// Construct an absl::Time from the system clock.
absl::Time t1 = absl::Now();

// When formatting a time, a time zone should be passed.
absl::TimeZone utc =  absl::UTCTimeZone();
std::cout << absl::FormatTime(t1, utc);

[skottmckay]

What's the difference between absl::date and the date library from Howard Hinnant that we use? Both are third-party aren't they?

I would have assumed the latter is closer to what is in the C++20 standard given Howard Hinnant is on the C++ standards committee.

[snnn]

Howard Hinnant is out of maintenance. On the other hand, absl::date is not deprecated, and it is already in the list of ORT's dependencies. Anyway we only use it in very a few places. The change would be local.

You need to run clang-format on the changed files.

[skottmckay]

Howard Hinnant is out of maintenance. On the other hand, absl::date is not deprecated, and it is already in the list of ORT's dependencies. Anyway we only use it in very a few places. The change would be local.

I assume that's because it was added to the C++20 standard: https://github.com/HowardHinnant/date#standardization

Ideally we'd only use one date library. If there's other functionality from absl::date we need I'm fine with that being the choice (assuming no significant binary size impact). But if this is all short term and we expect the C++20 features to remove the need for a third part date library I'd leave things as-is for now.

[mszhanyi]

/azp run Linux GPU CI Pipeline

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Azure Pipelines successfully started running 1 pipeline(s).

[snnn]

/azp run ONNX Runtime Web CI Pipeline

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).

[snnn]

The file still includes the third-party "date.h" header file, even when timestamp_ns refers to std::chrono