Kernel: Don't log profile data before/after the process/thread lifetime

There were a few cases where we could end up logging profiling events
before or after the associated process or thread exists in the profile:

After enabling profiling we might end up with CPU samples before we
had a chance to synthesize process/thread creation events.

After a thread exits we would still log associated kmalloc/kfree
events. Instead we now just ignore those events.

Kernel/Scheduler.h

@@ -43,7 +43,6 @@ public:
     static void leave_on_first_switch(u32 flags);
     static void prepare_after_exec();
     static void prepare_for_idle_loop();
-    static bool colonel_initialized();
     static Process* colonel();
     static void idle_loop(void*);
     static void invoke_async();