GEOT-4925 BandProcessTest.testROI fails with native JAI

Conflicts:

	modules/unsupported/process-raster/src/test/java/org/geotools/process/raster/BandProcessTest.java
Merge pull request #578 from n-lagomarsini/GEOT-4925_12x

GEOT-4925 BandProcessTest.testROI fails with native JAI (Backport on 12.x)