profiler: Report CPU times and use them to compute "missed" ticks.

This shows that the profiler is still pretty broken, because we
are missing quite a lot of ticks on average. One run of
"profile pkgman search" here produced an output with 66 total ticks
and 423 (!) missed ticks. A brief run of WebPositive was not quite
as bad (main thread: 1078 total ticks, 157 missed ticks.)

Change-Id: Idfc34534e66eff0fe7e948fcc3576be09db879a3
Reviewed-on: https://review.haiku-os.org/c/haiku/+/7820
Reviewed-by: waddlesplash <[email protected]>
Tested-by: Commit checker robot <[email protected]>
Reviewed-by: Adrien Destugues <[email protected]>

headers/os/kernel/debugger.h

@@ -622,6 +622,7 @@ typedef struct {
 										//   <sample 1> ... <sample stack_depth>
 	bool				stopped;		// if true, the thread is no longer
 										// being profiled
+	bigtime_t			last_cpu_time;	// only set if "stopped" is
 } debug_profiler_update;
 
 // B_DEBUGGER_MESSAGE_HANDED_OVER

headers/private/system/system_profiler_defs.h

@@ -112,12 +112,14 @@ struct system_profiler_thread_added {
 	team_id		team;
 	thread_id	thread;
 	char		name[B_OS_NAME_LENGTH];
+	bigtime_t	cpu_time;
 };
 
 // B_SYSTEM_PROFILER_THREAD_REMOVED
 struct system_profiler_thread_removed {
 	team_id		team;
 	thread_id	thread;
+	bigtime_t	cpu_time;
 };
 
 // B_SYSTEM_PROFILER_IMAGE_ADDED