Prevent logging exceptions twice when debugger is opened

[hernanmd]

Change logDebuggerStackToFile default setting to false since when set to true, it makes the debug session log twice on every request as reported in #15620.

[guillep]

Maybe you would like to discuss this with @StevenCostiou ?

If Pharo is already logging exceptions, why should the debugger do it also?
My point here is that maybe the code of this setting should just be removed, but I'm not sure :).
Otherwise, changing the setting looks like it's not solving the cause of the problem but its consequence, right? People with a bad setting could also have a bad experience, and not understand where it comes from.
In other words: if the setting has no value, why having it?

[StevenCostiou]

After discussion, we propose to merge this PR and open an issue to specifically discuss the need for a second mechanism.
It is not clear right now if we do or not.
However not logging upon debugger opening can improve a bit the speed? - and we need to gain avery possible bit of speed in the debugger ;)

[hernanmd]

Ok, I created another issue for this: #15810

[Ducasse]

I merge as requeted.

[daniels220]

Dang, I've been thinking about saying something about this for a long time, just now getting to it—wish I'd slipped my thoughts in sooner, because:

I think, instead, the system should skip the unconditional logging to the file, in UIManager>>requestDebuggerOpeningFor:, allowing the existing setting to do exactly what it says—control whether the stack is logged at all when opening a debugger. In which case I think true is a sensible default. As a fallback we should also log in requestDebuggerOpeningFor: if OupsDebuggerSystem is not present.

[guillep]

Dang, I've been thinking about saying something about this for a long time, just now getting to it—wish I'd slipped my thoughts in sooner, because:

I think, instead, the system should skip the unconditional logging to the file, in UIManager>>requestDebuggerOpeningFor:, allowing the existing setting to do exactly what it says—control whether the stack is logged at all when opening a debugger. In which case I think true is a sensible default. As a fallback we should also log in requestDebuggerOpeningFor: if OupsDebuggerSystem is not present.

I like the idea :)

[daniels220]

Actually, I'm going to kinda take that back—but I'm also going to put my actual comment on #15810, since that's the open issue.