Improve automatic module handling in module graph construction

Add all automatic modules to roots if at least one automatic module is
added, as per
http://cr.openjdk.java.net/~mr/jigsaw/spec/api/java/lang/module/package-summary.html

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/autoA/foo/Foo.java

@@ -0,0 +1,3 @@
+package foo;
+
+public class Foo {}

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/autoB/bar/Bar.java

@@ -0,0 +1,3 @@
+package bar;
+
+public class Bar {}

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/main.txt

@@ -0,0 +1 @@
+OK

compiler/testData/javaModules/unnamedAgainstSeveralAutomatic/main/usage.kt

@@ -0,0 +1,6 @@
+import foo.Foo
+import bar.Bar
+
+fun usage(): String {
+    return "${Foo()}${Bar()}"
+}