[Issue 21058] __traits(getOverloads) forgets "this" with third argument or if first overload is a template

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=21058

--- Comment #1 from Richard Manthorpe <rmanth at gmail.com> ---
Ignore the third assert for struct B, that's kind of unrelated, more similar to
https://issues.dlang.org/show_bug.cgi?id=18969

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