[Issue 22416] New: Unify polyImpl implementations

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=22416

          Issue ID: 22416
           Summary: Unify polyImpl implementations
           Product: D
           Version: D2
          Hardware: x86
                OS: All
            Status: NEW
          Severity: trivial
          Priority: P1
         Component: druntime
          Assignee: nobody at puremagic.com
          Reporter: bcallah at openbsd.org

This is a follow-up to issue 22393.

As requested as a follow-up in DRuntime pull request #8285, unify the assembly
implementations of polyImpl.

This moves Linux, the BSDs, and Solaris to a single common GenericPosixVersion.
The assembly for Windows and OSX are different from the Posix version, and are
different from each other, so Windows and OSX are left alone.

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