RFR: 8327460: Compile tests with the same visibility rules as product code [v2]

[Alan Bateman]

On Wed, 6 Mar 2024 13:43:00 GMT, Magnus Ihse Bursie <ihse at openjdk.org> wrote:

>> Currently, our symbol visibility handling for tests are sloppy; we only handle it properly on Windows. We need to bring it up to the same levels as product code. This is a prerequisite for [JDK-8327045](https://bugs.openjdk.org/browse/JDK-8327045), which in turn is a building block for Hermetic Java.
>
> Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Update line number for dereference_null  in TestDwarf

Good cleanup.

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Marked as reviewed by alanb (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/18135#pullrequestreview-1927041103