JSR 199: JavaCompilerTool and Tool must specify version of JLS and JVMS

After 6327885 JavaCompilerTool and Tool will include wording like this:

 * <p>An object implementing this interface must implement the Java
 * Language Specification and generate class files conforming to the
 * Java Virtual Machine specification. It must support the latest
 * versions of these specifications that are supported by the Java
 * virtual machine in which the object is created.

However, which version of the JLS or JVMS?

One possible solution to this problem is to have a method which returns
a list of supported source versions.