Issue 9259 - Passing an array of pointers to a typesafe vararg is broken

http://d.puremagic.com/issues/show_bug.cgi?id=9259

Root issue: Implicit conversion from `T[]` to `T*` is incorrectly deduced to `MATCHexact`. It should always be `MATCHconvert`, as same as `TypeSArray::implicitConvTo`.

Related issue: Implicit conversion from `T[]` to `T*` had been a deprecated language feature. But from 2.061, it is accidentally enabled in default. See [here](https://github.com/D-Programming-Language/dmd/pull/1287#issuecomment-12080557).