Handle the case when pid replacement is not needed

[cshung]

Fixing a case I missed in #70764. In case {pid} is not found in the file name, the existing code would use an uninitialized buffer, which is not good.

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Issue Details

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Fixing a case I missed in #70764. In case {pid} is not found in the file name, the existing code would use an uninitialized buffer, which is not good.

Author:	cshung
Assignees:	cshung
Labels:	area-GC-coreclr
Milestone:	7.0.0

[mrsharm]

LGTM!

[noahfalk]

The new function looks potentially error prone for future usage, I'd suggest changing it to remove the sharp edges.

[noahfalk]

The memory management rules of doing this feel error prone if sometimes we are returning a pointer to one buffer and other times we are returning a pointer to a different buffer. I'd suggest copying logFilename to fileName, make the return type void again, and the caller will always use fileName as before.

I don't think any of the callers that currently exist have an issue here, but I worry that it would be easy to create a new caller in the future that did have an issue.