[Issue 10258] Add hasAccess trait

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=10258
Issue 10258 depends on issue 10267, which changed state.

Issue 10267 Summary: Access checks should be relaxed in some contexts
https://issues.dlang.org/show_bug.cgi?id=10267

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

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