reversed gcov to work the old way - the worst thing that can happen 
    if slave and master execute the same code at the same time is that
    we get a lesser  count on the code branch execution, but in any case,
    it will be at least counted once, which is really all we care.
    
    Besides, the source tracking is most likely not thread safe, but this
    is ok for the same reason.


mysql-test/mysql-test-run:
  reversed gcov to work the old way - the worst thing that can happen 
  if slave and master execute the same code at the same time is that
  we get a lesser  count on the code branch execution, but in any case,
  it will be at least counted once, which is really all we care.
  
  Besides, the source tracking is most likely not thread safe, but this
  is ok for the same reason.