[SPARK-37785][SQL][CORE] Add Utils.isInRunningSparkTask

[HyukjinKwon]

What changes were proposed in this pull request?

This PR proposes to add Utils.isInRunningSparkTask to see if the codes are running on tasks e.g., on executors.

Why are the changes needed?

There is currently no single call to see if we're in a running Spark task (e.g., in executors). TaskContext.get == null is being used for that way. We should better explicitly factor out to Utils.

Does this PR introduce any user-facing change?

No, dev-only.

How was this patch tested?

Existing unittests should cover this case.

[dongjoon-hyun]

+1, LGTM.

[JoshRosen]

Just brainstorming aloud here:

Is the name isAtExecutorSide potentially confusing in the context of local mode (since in that case we don't have separate executor processes)?

I suppose it makes sense if we think of "at the executor side" as meaning

"in the context of a running Spark task"

instead of meaning

"not in the driver JVM".

If we wanted to be more precise, maybe we could call this Utils.inRunningSparkTask or something like that.

I don't feel super strongly about this. I mostly just want to flag the potential for ambiguity in case a new developer uses this method expecting the "not in the driver JVM" semantic.

[HyukjinKwon]

Yeah, I think it's better to be specific on what it means. Let me change like that.

[mridulm]

With the rename, it looks good to me.

[HyukjinKwon]

Thanks all!
Merged to master!