RFR: 8370196: C2: Improve (U)MulHiLNode::MulHiValue [v5]

[Zihao Lin]

> If nodes both are constant, support constant folding.

Zihao Lin has updated the pull request incrementally with one additional commit since the last revision:

  Apply suggestion from @eme64
  
  Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/28097/files
  - new: https://git.openjdk.org/jdk/pull/28097/files/c840a8c8..db57746d

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=28097&range=04
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=28097&range=03-04

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/28097.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28097/head:pull/28097

PR: https://git.openjdk.org/jdk/pull/28097