RFR: 8369167: C2: refactor LShiftINode/LShiftLNode Value/Identity/Ideal [v6]

[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 incrementally with one additional commit since the last revision:

  review

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/27725/files
  - new: https://git.openjdk.org/jdk/pull/27725/files/6865e1c4..29edbe64

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27725&range=05
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27725&range=04-05

  Stats: 15 lines in 1 file changed: 1 ins; 12 del; 2 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