Adding a simple profile for depur

The profiler can count how many executions each line had for a given
stack trace and order them. No time information yet.
Making posit a lot faster.

Based on the new profiler, some key inneficiences were discovered
on the posit runner. This commit fixes them and makes everything
faster:

  - The scope was preventing the timeout and tracing commands to
    be cached in variables. Moved them from posit_external to
    posit_process.
  - The previous error mode grep is now execute only once, not
    at each test. Error reporting is still set and restored
    on each unit.
  - The tracer was moved, so a new function for each reporting
    mode file was added to provide the filter for the depuration
    on each mode. This function is only called once now.
  - Tests were changed accordingly.
  - Added extra sort options for depur profile