Release Note: Added FileSystems.newFileSystem(Path, Map<String, ?>) Method

Three new methods have been added to `java.nio.file.FileSystems` to make it easier to use file system providers that treat the contents of a file as a file system.

- `newFileSystem(Path)`
- `newFileSystem(Path, Map<String, ?>)`
- `newFileSystem(Path, Map<String, ?>, ClassLoader)`

The addition of `newFileSystem(Path, Map<String, ?>)` creates a source (but not binary) compatibility issue for code that has been using the existing 2-arg `newFileSystem(Path, ClassLoader)` and specifying the class loader as `null.` For example, the following cannot be compiled because the reference to `newFileSystem` is ambiguous:

`FileSystem fs = FileSystems.newFileSystem(path, null);`

To avoid the ambiguous reference, this code needs to be modified to cast the second parameter to `java.lang.ClassLoader`.