[Issue 20933] druntime: core.thread doesn't support shadow stack

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=20933
Issue 20933 depends on issue 24043, which changed state.

Issue 24043 Summary: DMD does not emit IBT/BTI instructions
https://issues.dlang.org/show_bug.cgi?id=24043

           What    |Removed                     |Added
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             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

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