CUPSPrinter treats values of an ImageableArea from PPD files as x, y coordinates of the lower left corner and
width, height of imageable area. But as described in the PostScript Printer Description File Format Specification,

"The bounding box value of *ImageableArea is given as four real numbers, representing the x and y coordinates of the
lower left and upper right corners of the region, respectively".

The last two numbers should be treated as coordinates.

Reproducer:

1. Install new printer with provided PPD file or add the following line to an existing PPD:
*ImageableArea A4/A4: "9 9 586 833"
2. Run reproducer ImageableAreaTest.

Expected: Page width: 595,275581 height: 841,889740.
          Lower left corner: x:9,000000 y:9,000000,
          Upper right corner: x:586,000000 y:833,000000.
Actual: Page width: 595,275581 height: 841,889740
          Lower left corner: x:9,000000 y:8,889435,
          Upper right corner: x:595,000671 y:841,889740.