RFR: 8366357: C2 SuperWord: refactor VTransformNode::apply with VTransformApplyState [v2]

[Emanuel Peter]

> I'm working on **cost-modeling**, and am integrating some smaller changes from this proof-of-concept PR: https://github.com/openjdk/jdk/pull/20964
> 
> This is a **pure refactoring** - no change in behaviour. I'm presenting it like this because it will make reviews easier.
> 
> The goal here is that `VTransformNode::apply` only needs a single argument. This is important, as we will soon add more components that need to be updated during apply. That way, we can simply add more parts to `VTransformApplyState`, and do not need to add more arguments to VTransformNode::apply.
> 
> And yes: I have considering passing the `apply_state` as `const`. While this may be possible with the current code state, the upcoming changes from https://github.com/openjdk/jdk/pull/20964 will require non-const access to the `apply_state` (e.g. for `set_memory_state`).

Emanuel Peter has updated the pull request incrementally with one additional commit since the last revision:

  Update src/hotspot/share/opto/vtransform.hpp
  
  Co-authored-by: Christian Hagedorn <christian.hagedorn at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26987/files
  - new: https://git.openjdk.org/jdk/pull/26987/files/4dbbaa8d..d91d66db

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26987&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26987&range=00-01

  Stats: 1 line in 1 file changed: 0 ins; 1 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/26987.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26987/head:pull/26987

PR: https://git.openjdk.org/jdk/pull/26987