RFR: 8254129: IR Test Framework to support regex-based matching on the IR in JTreg compiler tests [v8]

[Christian Hagedorn]

> This RFE provides an IR test framework to perform regex-based checks on the C2 IR shape of test methods emitted by the VM flags `-XX:+PrintIdeal` and `-XX:+PrintOptoAssembly`. The framework can also be used for other non-IR matching (and non-compiler) tests by providing easy to use annotations for commonly used testing patterns and compiler control flags.
> 
> The framework is based on the ideas of the currently present IR test framework in [Valhalla](https://github.com/openjdk/valhalla/blob/e9c78ce4fcfd01361c35883e0d68f9ae5a80d079/test/hotspot/jtreg/compiler/valhalla/inlinetypes/InlineTypeTest.java) (mainly implemented by @TobiHartmann) which is being used with great success. This new framework aims to replace the old one in Valhalla at some point.
> 
> A detailed description about how this new IR test framework works and how it is used is provided in the [README.md](https://github.com/chhagedorn/jdk/blob/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/README.md) file and in the [Javadocs](https://github.com/chhagedorn/jdk/blob/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/doc/jdk/test/lib/hotspot/ir_framework/package-summary.html) written for the framework classes.
> 
> To finish a first version of this framework for JDK 17, I decided to leave some improvement possibilities and ideas to be followed up on in additional RFEs. Some ideas are mentioned in "Future Work" in [README.md](https://github.com/chhagedorn/jdk/blob/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/README.md) and were also created as subtasks of this RFE.
> 
> Testing (also described in "Internal Framework Tests in [README.md](https://github.com/chhagedorn/jdk/blob/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/README.md)):
> There are various tests to verify the correctness of the test framework which can be found as JTreg tests in the [tests](https://github.com/chhagedorn/jdk/tree/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/tests) folder. Additional testing was performed by converting all compiler Inline Types test of project Valhalla (done by @katyapav in [JDK-8263024](https://bugs.openjdk.java.net/browse/JDK-8263024)) that used the old framework to the new framework. This provided additional testing for the framework itself. We ran the converted tests with all the flag settings used in hs-tier1-9 and hs-precheckin-comp. For sanity checking, this was also done with a sample IR test in mainline.
> 
> Some stats about the framework code added to [ir_framework](https://github.com/chhagedorn/jdk/tree/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework):
> 
> -  without the [Javadocs files](https://github.com/chhagedorn/jdk/tree/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/doc) : 60 changed files, 13212 insertions, 0 deletions.
>    - without the [tests](https://github.com/chhagedorn/jdk/tree/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/tests)  and [examples](https://github.com/chhagedorn/jdk/tree/aa005f384a4567c6c0b5f08f7c5df57f705dc540/test/lib/jdk/test/lib/hotspot/ir_framework/examples) folder: 40 files changed, 6781 insertions
>       - comments: 2399 insertions (calculated with `git diff --cached !(tests|examples) | grep -c -E "(^[+-]\s*(/)?*)|(^[+-]\s*//)"`)
>       - which leaves 4382 lines of code inserted 
> 
> Big thanks to:
> - @TobiHartmann for all his help by discussing the new framework and for providing insights from his IR test framework in Valhalla.
> - @katyapav for converting the Valhalla tests to use the new framework which found some harder to catch bugs in the framework and also some actual C2 bugs.
> - @iignatev for helping to simplify the framework usage with JTreg and with the framework internal VM calling structure.
> - and others who provided valuable feedback.
> 
> Thanks,
> Christian

Christian Hagedorn has updated the pull request incrementally with four additional commits since the last revision:

 - Remove TestFramework: both runWithScenarios, both runWithHelperClasses, and one runWithFlags method to make interface cleaner/simpler, update internal tests accordingly
 - Minor improvements, comment fixes, and test fixes
 - Rename TestFrameworkPrepareFlags -> FlagVM and rename TestFrameworkExecution -> TestVM
 - Apply review comments: Extract Test classes into own files, extract Flag and Test VM processes into own class, replace socket-based flag VM communication with file-based and clean up socket usage of test VM, fix useless processing of hotspot-pid files if no IR rules are applied

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/3508/files
  - new: https://git.openjdk.java.net/jdk/pull/3508/files/90a0064d..d6c72ec6

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=3508&range=07
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=3508&range=06-07

  Stats: 4113 lines in 31 files changed: 2056 ins; 1938 del; 119 mod
  Patch: https://git.openjdk.java.net/jdk/pull/3508.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/3508/head:pull/3508

PR: https://git.openjdk.java.net/jdk/pull/3508