Pcbnew: fix teardrop generation for pads having different shapes by layer.

Teardrop generator used pad::HitTest not testing the hit of a specific layer.
It created false test for some complex pads. Now use a test specific to a layer.

Fixes https://gitlab.com/kicad/code/kicad/-/issues/21560

(cherry picked from commit 963aa47778)

pcbnew/pad.cpp

@@ -1445,6 +1445,20 @@ void PAD::GetMsgPanelInfo( EDA_DRAW_FRAME* aFrame, std::vector<MSG_PANEL_ITEM>&
 }
 
 
+bool PAD::HitTest( const VECTOR2I& aPosition, int aAccuracy, PCB_LAYER_ID aLayer ) const
+{
+    VECTOR2I delta = aPosition - GetPosition();
+    int      boundingRadius = GetBoundingRadius() + aAccuracy;
+
+    if( delta.SquaredEuclideanNorm() > SEG::Square( boundingRadius ) )
+        return false;
+
+    bool contains = GetEffectivePolygon( aLayer, ERROR_INSIDE )->Contains( aPosition, -1, aAccuracy );
+
+    return contains;
+}
+
+
 bool PAD::HitTest( const VECTOR2I& aPosition, int aAccuracy ) const
 {
     VECTOR2I delta = aPosition - GetPosition();

pcbnew/pad.h

@@ -822,6 +822,11 @@ public:
     bool HitTest( const BOX2I& aRect, bool aContained, int aAccuracy = 0 ) const override;
 
 
+    /**
+     * return true if hit test on the specified layer
+     */
+    bool HitTest( const VECTOR2I& aPosition, int aAccuracy, PCB_LAYER_ID aLayer ) const;
+
     /**
      * Recombines the pad with other graphical shapes in the footprint
      *

pcbnew/teardrop/teardrop.cpp

@@ -236,8 +236,11 @@ void TEARDROP_MANAGER::UpdateTeardrops( BOARD_COMMIT& aCommit,
                 continue;
             }
 
-            if( pad->HitTest( track->GetStart() ) && pad->HitTest( track->GetEnd() ) )
-                // The track is entirely inside the pad; cannot create a teardrop
+            bool startHitsPad = pad->HitTest( track->GetStart(), 0, track->GetLayer() );
+            bool endHitsPad = pad->HitTest( track->GetEnd(), 0, track->GetLayer() );
+
+            // if the track is entirely inside the pad, cannot create a teardrop
+            if( startHitsPad && endHitsPad )
                 continue;
 
             // Skip case where pad and the track are within a copper zone with the same net

pcbnew/teardrop/teardrop_utils.cpp

@@ -717,10 +717,10 @@ bool TEARDROP_MANAGER::computeTeardropPolygon( const TEARDROP_PARAMETERS& aParam
     {
         PAD* pad = static_cast<PAD*>( aOther );
 
-        if( pad->HitTest( pointA ) )
+        if( pad->HitTest( pointA, 0, layer ) )
             return false;
 
-        if( pad->HitTest( pointB ) )
+        if( pad->HitTest( pointB, 0, layer ) )
             return false;
     }