Fixed small memory leak in libprofile (#141739)

Inside `getCurFilename`, there is this code snippit
```
if (!lprofCurFilename.FilenamePat || !lprofCurFilename.FilenamePat[0])
    return 0;
```
If this is true, we return `"\0"`, but would leak the memory in
`FilenameBuf`.
This pull request adds a free before then to properly free the memory.
There was already a check that we allocated memory, so there is no need
to worry about freeing unallocated memory.

GitOrigin-RevId: 2b1ebef8b8a5af7092de80daafd2743683d0e8c8
1 file changed