instancer: remap axis indices in instantiateFeatureVariations
instancer: remap axis indices in instantiateFeatureVariations

ConditionTable.AxisIndex needs to change when dropping axes, to
refer to the same axis in the modified fvar.axes array.

There was also another bug when a condition was not met,
and the `applies` flag (initialised to `True`) was not set to
`False`, thus substutions were incorrectly applied.

fonttools/fonttools,googlefonts/fonttools