The following tests take much longer to execute on Windows, as compared to other platforms:
java/nio/channels/FileChannel/TransferTo6GBFile.java - 91 seconds
java/nio/channels/FileChannel/Transfer4GBFile.java - 85 seconds
java/nio/channels/FileChannel/Transfer2GPlus.java - 85 seconds

On other platforms the same tests complete under a second.
The tests are run in exclusive mode, which means that they are never run in parallel, which slows down tier2 testing even more.

We can probably speed up these tests by making sure that the test files are created with StandardOpenOption.SPARSE.