kernel: Add k_thread_runtime_stats_is_enabled function

[rruuaanng]

Add 'k_thread_runtime_stats_is_enabled' to 'usage.c', which's used to check whether runtime statistics collection is enabled for a thread.

It can determine whether the thread has enabled runtime statistics collection when the program is running. It allows users to add conditional statements based on this function when using it.

for example:

void f()
{
    // Assume there is a thread id
    if (k_thread_runtime_stats_is_enabled(id)) {
        /* do something */
    }
    ...
}

And it can provide a complete support when similar operations are needed. for example enable, disable, is_enabled.
For example, its use in the implementation of CLOCK_THREAD_CPUTIME_ID actually lacks k_thread_runtime_stats_is_enabled, which makes the entire function impossible to implement safely. It is necessary.

..

[cfriedt]

Thanks for all of the POSIX clock work.

Just a question / suggestion regarding runtime function call overhead.

[cfriedt]

Just some suggestions around CONFIG_POSIX_THREAD_CPUTIME

[rruuaanng]

I've made change, Please riewer again!

[peter-mitsis]

Kernel side seems reasonable to me.

[cfriedt]

@rruuaanng - needs a rebase again to resolve the merge conflict, but it would also be a good opportunity to add @ycsin's change request as well.

[andyross]

One more nitpick that I can't get past. But that's my only complaint, feel free to assume +1 once resolved.

[rruuaanng]

Please review them again! @cfriedt @ycsin @andyross. If there are no other points, I will be ready to rebase, thanks.

[ycsin]

🥳