Altium PCB: fix padstack shapes import on F.Cu.

pcbnew/padstack.cpp

@@ -989,6 +989,8 @@ PCB_LAYER_ID PADSTACK::EffectiveLayerFor( PCB_LAYER_ID aLayer ) const
 
             // We're asked for an inner copper layer not present in the board.  There is no right
             // answer here, so fall back on the front shape
+            wxFAIL_MSG( "Asked for inner padstack layer not present on the board" );
+
             return ALL_LAYERS;
         }
 

pcbnew/pcb_io/altium/altium_pcb.cpp

@@ -3499,7 +3499,11 @@ void ALTIUM_PCB::ConvertPads6ToFootprintItemOnCopper( FOOTPRINT* aFootprint, con
         {
             size_t i = 0;
 
-            for( PCB_LAYER_ID layer : LAYER_RANGE( In2_Cu, In30_Cu, MAX_CU_LAYERS ) )
+            LSET intLayers = aFootprint->BoardLayerSet();
+            intLayers &= LSET::InternalCuMask();
+            intLayers.set( In1_Cu, false ); // Already handled above
+
+            for( PCB_LAYER_ID layer : intLayers )
             {
                 setCopperGeometry( layer, aElem.sizeAndShape->inner_shape[i],
                                    VECTOR2I( aElem.sizeAndShape->inner_size[i].x,