[Issue 16379] merging coverage sometimes overwrites existing results

[via Digitalmars-d-bugs]

https://issues.dlang.org/show_bug.cgi?id=16379

greensunny12 at gmail.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |greensunny12 at gmail.com

--- Comment #1 from greensunny12 at gmail.com ---
The issue seems to be that `doTest` is called 4x for std.stdio - see this PR
with some explanation on this behavior.

https://github.com/dlang/druntime/pull/1629

--