Revert: draw alpha bitmaps directly to print graphics on macOS

This partially reverts commit fa3dd1c3a1.
Apparently, the special handling of alpha bitmaps when printing on macOS
is no longer needed and the alpha blending code used on other platforms
now works as expected on macOS.

Change-Id: Ib72e57ec679971c8db06160ae0354c8ba45be91e
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/190496
Tested-by: Jenkins
Reviewed-by: Patrick Luby <guibomacdev@gmail.com>

vcl/source/gdi/print.cxx

@@ -192,14 +192,6 @@ void Printer::DrawDeviceBitmapEx( const Point& rDestPt, const Size& rDestSize,
                                 const Point& rSrcPtPixel, const Size& rSrcSizePixel,
                                 Bitmap& rBmp )
 {
-#ifdef MACOSX
-    // tdf#164354 draw alpha bitmaps directly to print graphics on macOS
-    // On macOS, there are no known problems drawing semi-transparent
-    // bitmaps so just draw the alpha bitmap directly without any blending.
-    AlphaMask aAlpha = rBmp.CreateAlphaMask();
-    aAlpha.Invert();
-    DrawDeviceAlphaBitmap( Bitmap(rBmp.CreateColorBitmap(), aAlpha), rDestPt, rDestSize, rSrcPtPixel, rSrcSizePixel );
-#else
     if( rBmp.HasAlpha() )
     {
         // #107169# For true alpha bitmaps, no longer masking the
@@ -213,7 +205,6 @@ void Printer::DrawDeviceBitmapEx( const Point& rDestPt, const Size& rDestSize,
     {
         ImplPrintTransparent( rBmp, rDestPt, rDestSize, rSrcPtPixel, rSrcSizePixel );
     }
-#endif
 }
 
 void Printer::EmulateDrawTransparent ( const tools::PolyPolygon& rPolyPoly,