Added multi-module tests on incremental compilation.

Changing code wasn't required, Java's incremental caches were enough.

jps-plugin/testData/incremental/multiModule/circularDependencyClasses/module2_b.kt.new

@@ -0,0 +1,11 @@
+package b
+
+class B: a.A() {
+   fun f() {
+   }
+}
+
+open class BB {
+   fun f() {
+   }
+}