java/nio/channels/FileChannel/FileExtensionAndMap.java uses @ignore w/o bug id

java/nio/channels/FileChannel/FileExtensionAndMap.java has '@ignore This test has huge disk space requirements'; canonically, @ignore should be followed by the id of the bug which describes the problem and will be used to eventually fix it.

note: if this test is inapplicable for regular/automated execution due to its requirement for disk space, it's better to use '/manual' option so the test will be excluded from automated testing, yet will be easy to find and run in manual testing. an alternative solution might to update the test to 1st check available disk space and throw SkippedException if there isn't enough.