Tests Overview pane calculation in FlameChart for different width = 2^n with n in range 4 - 0.
      Also tests loading of a legacy nodes format, where nodes were represented as a tree.

log: 14,14,1,1,1,1,1,1,1,1,1,1,1,11,15,1
log: 14,1,1,1,1,1,11,15
log: 14,1,1,15
log: 14,15
log: 15