Medium: PE: Bug PM1 - Failcount applies to all instances of non-unique clone
If instance N fails on nodeX and gets a score of -100 as a result, then that
score is applied to all the other instances as well. This helps to avoid clone
shuffling as also seen in Bug LF1852

Mercurial revision: dbea4bb46c446d90734e102c2b65b9f35e4847db