6989505: java.awt.Robot's getPixelColor treats not fully opaque Window as fully transparent.
Summary: Use ::CreateDC() instead of ::GetDC()
Reviewed-by: art, dcherepanov
^build/
^dist/
/nbproject/private/
^src/share/tools/hsdis/build/
^src/share/tools/IdealGraphVisualizer/[a-zA-Z0-9]*/build/
^src/share/tools/IdealGraphVisualizer/build/
^src/share/tools/IdealGraphVisualizer/dist/