[Issue 18630] std.math must CTFE

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=18630
Issue 18630 depends on issue 17705, which changed state.

Issue 17705 Summary: std.math.isFinite cannot run at compile-time
https://issues.dlang.org/show_bug.cgi?id=17705

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

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