Debugger: Fix handling of team_id clashes.

TeamDebugger:
- Add accessor to query whether the debugger's interface is a post mortem core
  rather than a live team.

TargetHostInterface:
- When asked to locate a team debugger by team_id, as is done for attach
  requests to determine if we already have an existing instance attached, skip
  over post mortems. This takes care of the potential problem of detecting a
  core instance with the same team_id as a live team, and consequently refusing
  the attach request.
- When a team debugger quits, use its actual pointer to look it up rather than its
  team ID, as we could otherwise potentially remove the wrong one in the case of a
  clash.

src/apps/debugger/controllers/TeamDebugger.h

@@ -51,6 +51,8 @@ public:
 
 			team_id				TeamID() const	{ return fTeamID; }
 
+			bool				IsPostMortem() const { return fIsPostMortem; }
+
 			int					ArgumentCount() const
 									{ return fCommandLineArgc; }
 			const char**		Arguments() const
@@ -245,6 +247,7 @@ private:
 			SettingsManager*	fSettingsManager;
 			::Team*				fTeam;
 			team_id				fTeamID;
+			bool				fIsPostMortem;
 			ThreadHandlerTable	fThreadHandlers;
 									// protected by the team lock
 			ImageHandlerTable*	fImageHandlers;