RFR: 8367657: C2 SuperWord: NormalMapping demo from JVMLS 2025

[Emanuel Peter]

Demo from here:
https://inside.java/2025/08/16/jvmls-hotspot-auto-vectorization/

Cleaned up and enhanced with a JTREG and IR test.
I also added some additional "generated" normal maps from height functions.
And I display the resulting image side-by-side with the normal map.

I decided to put it in a new directory `compiler.galery`, anticipating other compiler tests that are both visually appealing (i.e. can be used for a "galery") and that we may want to back up with other tests like IR testing.

Here some snapshots:
<img width="2000" height="991" alt="image" src="https://github.com/user-attachments/assets/a693fac8-ecf0-43f2-914b-25f76c2f425d" />
<img width="2000" height="997" alt="image" src="https://github.com/user-attachments/assets/c2202e6b-6a90-4f90-a3ca-b73304e25905" />
<img width="1997" height="992" alt="image" src="https://github.com/user-attachments/assets/0d6da304-6bb9-4b25-9a7b-72019b02d95e" />
<img width="1992" height="994" alt="image" src="https://github.com/user-attachments/assets/9f5f7426-0678-45af-a3eb-ac092c262d4c" />

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Commit messages:
 - more prints
 - comments
 - update
 - more details
 - documentation
 - IR rule
 - simplify timeout
 - handle timeouts, maybe a bit cluncky
 - fix path issuesg
 - add stand-alone
 - ... and 1 more: https://git.openjdk.org/jdk/compare/2826d170...1bdaf5fc

Changes: https://git.openjdk.org/jdk/pull/27282/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27282&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367657
  Stats: 659 lines in 4 files changed: 659 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/27282.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27282/head:pull/27282

PR: https://git.openjdk.org/jdk/pull/27282