RFR: 8369167: C2: refactor LShiftINode/LShiftLNode Value/Identity/Ideal

[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.

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Commit messages:
 - more
 - more
 - more
 - more
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 - fix

Changes: https://git.openjdk.org/jdk/pull/27725/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27725&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8369167
  Stats: 625 lines in 6 files changed: 368 ins; 170 del; 87 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