[9] Review request for 8040279 [macosx] Do not use the base image in the MultiResolutionBufferedImage constructor

[Alexander Scherbatiy]

Hello,
Could you review the fix:
  bug: https://bugs.openjdk.java.net/browse/JDK-8040279
  webrev: http://cr.openjdk.java.net/~alexsch/8040279/webrev.00

  MultiResolutionBufferedImage extends BufferedImage. In this case it 
needs to use the base image to write it to the BufferedImage.

  The fix renames MultiResolutionBufferedImage to 
MultiResolutionCahcedImage and does not use the BufferedImage as the 
super class.
  The base image is created and cached by demand.

  CImage now always returns MultiResolutionCahcedImage. All requested 
resolution variants are scaled by NSImage.

Thanks,
Alexandr.