Extend time quantum if not in marked 'interesting' code.

[LouisJenkinsCS]

Michael had the brilliant idea that instead of probabilistically cutting a time quantum short based on whether or not a thread is in marked 'interesting' code, but instead will just extend its time slice. Essentially modify this...

Persistent-Memory-Analysis-Tool/coregrind/m_scheduler/scheduler.c

Lines 1576 to 1579 in 7548f6f

	case VG_TRC_INNER_COUNTERZERO:
	/* Timeslice is out. Let a new thread be scheduled. */
	vg_assert(dispatch_ctr == 0);
	break;

Into this...

  case VG_TRC_INNER_COUNTERZERO:
         /* Timeslice is out.  Let a new thread be scheduled,
            but only if we’re running in “interesting” code. */
         vg_assert(dispatch_ctr == 0);
         if (!in_interesting_code) {  // determined somehow...
             // could optionally skip this reinitialization, with low probability
             dispatch_ctr = VG_(scheduling_quantum);
         }
         break;