Update SunJSSE section of JDK Providers guide to use keytool to list enabled cipher suites

In https://docs.oracle.com/en/java/javase/13/security/oracle-providers.html#GUID-7093246A-31A3-4304-AC5F-5FB6400405E2, under the section titled "Determining Current List of Cipher Suites Available by Default", this should be updated to use the new "keytool -showinfo -tls" command to list the enabled suites instead of having to compile and run the code listed. You might want to add a sentence at the end that says something like: "This does not include the suites that are disabled by the jdk.tls.disabledAlgorithms security property".