RFR: JDK-8278585: Drop unused code from OSThread

[David Holmes]

On Sun, 12 Dec 2021 07:12:19 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

> Gentle cleanup of OSThread, removes some unused functionality. No functional changes.
> 
> - both start proc and start param parameters are unused (when we create threads we always start with `thread_native_entry` as thread procedure). Removed members and constructor arguments (had always been called with NULL)
> - `valid_reposition_failure()` is unused, returns always false on all platforms. Used to return true on Solaris, but I could not find a caller even going back to jdk-8.
> - removed `thread_id_offset`, `thread_id_size`, both had been used at one time by C1 but not anymore.
> - Finally, removed the platform-independent stub for the windows-only `set_interrupted()`; replaced it with WINDOWS_ONLY at the only two places where it is invoked. Matter of taste, but I find this actually clearer than having a single-platform function looking like a generic one.
> 
> Thanks, Thomas

Hi Thomas,

This cleanup looks good!

Thanks,
David

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Marked as reviewed by dholmes (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/6809