JDK 9 RFR of 8164556: Drop AAC and FLAC from content type check in java/nio/file/Files/probeContentType/Basic.java

[Brian Burkhalter]

Please review at your convenience:

Issue:	https://bugs.openjdk.java.net/browse/JDK-8164556
Patch:	http://cr.openjdk.java.net/~bpb/8164556/webrev.00/

The file extensions for the AAC and FLAC audio encodings appear to map to different and unpredictable MIME types depending on the system configuration and these MIME types differ from the respective ones in the fall back content types files. The best option seems to remove these extensions from the test as the remaining extensions give predictable results.

Thanks,

Brian