RFR: 8325444: GHA: JDK-8325194 causes a regression

[George Adams]

On Wed, 7 Feb 2024 19:50:51 GMT, Christoph Langer <clanger at openjdk.org> wrote:

> The [change](https://github.com/openjdk/jdk/commit/d1c82156ba6ede4b798ac15f935289cfcc99d1a0) for [JDK-8325194](https://bugs.openjdk.org/browse/JDK-8325194) broke get-jtreg because the macro to determine the build jdk was not correct.
> 
> I fix this by reverting to the originally proposed way to use `$JAVA_HOME_17_<arch>`. I tried to use the bootstrap JDK in first place with the correct wiring but it turned out that the build of JTReg fails with that version, see [here](https://github.com/RealCLanger/jdk/actions/runs/7820130826/job/21334120478).

Marked as reviewed by gdams (Author).

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PR Review: https://git.openjdk.org/jdk/pull/17756#pullrequestreview-1868656028