RFR: 8371804: C2: Tighten up LoadNode::Value comments after JDK-8346184

[Vladimir Kozlov]

On Thu, 13 Nov 2025 14:30:10 GMT, Aleksey Shipilev <shade at openjdk.org> wrote:

> This confused me quite a bit in [JDK-8371581](https://bugs.openjdk.org/browse/JDK-8371581) investigations.
> 
> With [JDK-8346184](https://bugs.openjdk.org/browse/JDK-8346184), we have moved the block in `LoadNode::Value` that produced bottom values for the block that "If we are loading from a freshly-allocated object, produce a zero, if the load is provably beyond the header of the object." This comment is misleading, and really relates to the old place, which actually returns zeroes.
> 
> It would be better to clean this up to avoid further confusion. There should be no semantic change, only the cleanup.
> 
> Additional testing:
>  - [ ] GHA

Good.

-------------

Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28296#pullrequestreview-3462580358