lib.ptree: do not aggregate (ignore) counters that are symlinks
lib.ptree: do not aggregate (ignore) counters that are symlinks

This heuristic is intended to match global counters (e.g. intel_mp/pci device
stats) which are shared by multiple app instances (via symlinking) and prevent
them from being aggregated as if they were independent.

Igalia/snabbswitch,Igalia/snabb,Igalia/snabb,snabbco/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,snabbco/snabb,eugeneia/snabb,snabbco/snabb,eugeneia/snabb,alexandergall/snabbswitch,Igalia/snabb,snabbco/snabb,alexandergall/snabbswitch,eugeneia/snabb,Igalia/snabb,Igalia/snabbswitch,SnabbCo/snabbswitch,snabbco/snabb,alexandergall/snabbswitch,Igalia/snabb,alexandergall/snabbswitch,alexandergall/snabbswitch,eugeneia/snabb,Igalia/snabb,eugeneia/snabb,SnabbCo/snabbswitch,Igalia/snabb,eugeneia/snabb,snabbco/snabb,Igalia/snabb,eugeneia/snabb,alexandergall/snabbswitch,Igalia/snabbswitch,snabbco/snabb,SnabbCo/snabbswitch,eugeneia/snabb,Igalia/snabbswitch,Igalia/snabbswitch,snabbco/snabb,SnabbCo/snabbswitch