RFR: 8297384: Add IR tests for existing idealizations of arithmetic nodes [v3]

[Zhiqiang Zang]

> I noticed some idealizations have no associated IR tests so I included for them.

Zhiqiang Zang has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains five additional commits since the last revision:

 - Merge master.
 - include @bug and @summary for newly created ir test classes.
 - format.
 - format whitespace.
 - add some missing tests for existing idealizations.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/11049/files
  - new: https://git.openjdk.org/jdk/pull/11049/files/c0931397..bb92a752

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=11049&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=11049&range=01-02

  Stats: 53640 lines in 1037 files changed: 19606 ins; 20747 del; 13287 mod
  Patch: https://git.openjdk.org/jdk/pull/11049.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/11049/head:pull/11049

PR: https://git.openjdk.org/jdk/pull/11049