Track down why sectionSpacing needs to be scaled

sectionSpacing in flame_chart needs to be scaled otherwise negative padding values are generated.
Track down what the bug in the current logic is so that this can be avoided.

This is surprising to me that this needs to be scaled at all. This is supposed to be the vertical spacing between sections of the flame chart, and should be independent of the size of the rows (which would be affected by font size).

rowOffsetForTopPadding is the number of rows we want to offset for padding at the top of the flame chart. For example, we need more rows of padding in the timeline flame chart that has the timestamp grid at the top than we need in the Cpu profiler flame chart, which doesn't have anything to account for at the top.