RFR: 8267265: Use new IR Test Framework to create tests for C2 IGV transformations [v2]

[John Tortugo]

> Hi, can I please get some reviews for this Pull Request? Here is a summary of the changes:
> 
> - Add tests, using the new IR-based test framework, for several of the Ideal transformations on Add, Sub, Mul, Div, Loop nodes and some simple Scalar Replacement transformations.
> - Add more default IR regex's to IR-based test framework.
> - Changes to Sub, Div and Add Ideal nodes to that transformations on Int and Long types are the whenever possible same.
> - Changes to Sub*Node, Div*Node and Add*Node Ideal methods to fix some bugs and include new transformations.
> - New JTREG "ir_transformations" test group under test/hotspot/jtreg.

John Tortugo has updated the pull request incrementally with one additional commit since the last revision:

  Reverting changes to Ideal transformations. Removing failing tests. Reverting order of nodes in IRNode.

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Changes:
  - all: https://git.openjdk.java.net/jdk/pull/5135/files
  - new: https://git.openjdk.java.net/jdk/pull/5135/files/dabaf8fb..22565304

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=5135&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=5135&range=00-01

  Stats: 266 lines in 8 files changed: 70 ins; 184 del; 12 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5135.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5135/head:pull/5135

PR: https://git.openjdk.java.net/jdk/pull/5135