Even if there's a synchronisation mechanism between kernel32:debugger
and its children which ensures that child has finished writing to and
closed the blackbox logging file before reading it, there's no
guarantee that the file is not re-opened by another process: antivirus,
file indexing...
And according to [1], even the OS itself can still have opened references
to it.

So, always open/read the blackbox file in read share mode to work around
this issue.

Also, harden the code for potential errors, and be nicer in where
failures come from.

[1] https://learn.microsoft.com/en-us/windows-hardware/drivers/ifs/irp-mj-cleanup

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=53456Signed-off-by: Eric Pouech <eric.pouech@gmail.com>