THREAD_FREE: rely less on macros

[moonchen]

Move as much of the implementation of THREAD_FREE as possible into a type-safe function. This was already done for THREAD_ALLOC.

[bneradt]

Good change.

Do you think thread_free should be marked inline?

[moonchen]

Good change.

Do you think thread_free should be marked inline?

I don't know. We don't need it to comply with ODR since the function is a template function. My understanding is that modern compilers are already smart about whether to inline the function, so it's hard to say whether adding the keyword will help with performance.

[bneradt]

In case it's helpful, here's the clang analyzer report from the artifact's directory of the job:
https://ci.trafficserver.apache.org/job/Github_Builds/job/clang-analyzer/5363/artifact/output/11943/scan-build-2025-01-07-23-04-27-974869-ju80g4aa/index.html

[moonchen]

[approve ci autest]