Review Request JDK-8171323: generate dot file for java.se and java.se.ee with only API dependences

[Mandy Chung]

This updates the GenGraphs build tool to generate a dot file for
`java.se` and `java.se.ee` modules including API dependences only
that can be used to display Java SE module graph.

http://cr.openjdk.java.net/~mchung/jdk9/webrevs/8171323/webrev.00/

Mandy