RFR: 8369167: C2: refactor LShiftINode/LShiftLNode Value/Identity/Ideal [v4]

[Roland Westrelin]

> This change refactor code that's similar for LShiftINode and
> LShiftLNode into shared methods. I also added extra test cases to
> cover all transformations.

Roland Westrelin has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 10 commits:

 - review
 - Merge branch 'master' into JDK-8369167
 - review
 - sort headers
 - more
 - more
 - more
 - more
 - more
 - fix

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Changes: https://git.openjdk.org/jdk/pull/27725/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27725&range=03
  Stats: 617 lines in 6 files changed: 343 ins; 170 del; 104 mod
  Patch: https://git.openjdk.org/jdk/pull/27725.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27725/head:pull/27725

PR: https://git.openjdk.org/jdk/pull/27725