8385856: GHA: Consolidate architecture-specific steps in Windows CI workflows

[gdams]

Several steps in the Windows CI workflows are duplicated per architecture (x86.x64 / ARM64) where a single step with conditional expressions would suffice.

Changes:

• action.yml: Merge the two MSYS2 install steps and two path steps into one of each, using expressions for release and location.
• build-windows.yml: Merge the two toolchain check steps into one (conditional on bat file name), and merge the two toolchain install steps into one (component suffix already matches inputs.architecture).

This reduces duplication and makes future architecture additions simpler.

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Progress

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Issue

• JDK-8385856: GHA: Consolidate architecture-specific steps in Windows CI workflows (Enhancement - P4)

Reviewers

• Christoph Langer (@RealCLanger - Reviewer) 🔄 Re-review required (review applies to 8b08dfd7)

Reviewing

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[bridgekeeper]

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[openjdk]

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[mlbridge]

Webrevs

• 01: Full - Incremental (10f1297f)
• 00: Full (8b08dfd7)

[RealCLanger]

Looks good, assuming the GHA run succeeds and show no issues.

[shipilev]

One of the reasons why I asked @Luigi96 to have these steps split it to make X86 and AArch64 updates independent on each other. Things that I foresee can give us a headache going forward: msys2 versions, MSVC paths.

So unless we simplify in such a way those "platform-specific" things are selectable per job, we are good. But we are not there yet.

[gdams]

One of the reasons why I asked @Luigi96 to have these steps split it to make X86 and AArch64 updates independent on each other. Things that I foresee can give us a headache going forward: msys2 versions, MSVC paths.

So unless we simplify in such a way those "platform-specific" things are selectable per job, we are good. But we are not there yet.

I think we can use inputs here to still tidy up the code. Let me push another commit and see what you think

[gdams]

@shipilev let me know what you think now?

Note that it looks like there are some plans to include MSYS2 on the Windows ARM64 runners in the near future which would simplify this even further: actions/runner-images#14087