Fix closing sub-path created by MoveToPoint() in Direct2D

Because call to MoveToPoint() opens a new sub-path but doesn't open
a new D2D figure (this is to avoid the situation when multiple consequtive
calls to MoveToPoint() would open a spurious figures/paths, see c8fe811636),
we need to check when sub-path is being closed if we have a sub-patch
without figure and if so, a new figure has to be open to get a required
in this case 1-point figure/path.

src/msw/graphicsd2d.cpp

@@ -1813,6 +1813,13 @@ void wxD2DPathData::AddPath(const wxGraphicsPathData* path)
 // closes the current sub-path
 void wxD2DPathData::CloseSubpath()
 {
+    // If we have a sub-path open by call to MoveToPoint(),
+    // which doesn't open a new figure by itself,
+    // we have to open a new figure now to get a required 1-point path.
+    if ( !m_figureOpened && m_currentPointSet )
+    {
+        EnsureFigureOpen(m_currentPoint);
+    }
     // Close sub-path and close the figure.
     if ( m_figureOpened )
     {