COLRVariationMerger: fix logic in convertSubTablesToVarType
COLRVariationMerger: fix logic in convertSubTablesToVarType

Before we were too greedy in the way we converted subtables to VarType. E.g. If a PaintTransform wrapping a PaintRadialGradient contained variations in the Affine2x3, we would incorrectly convert also the gradient's ColorLine (and ColorStops) to VarColorLine, VarColorStop, etc. (even if the gradient was not variable!). Instead we want skip traversing a given subtable including its children when the predicate doesn't match.

fonttools/fonttools,googlefonts/fonttools