Move importsDumper to compiler plugin

plugins/imports-dumper/testData/simpleCase/c/JavaC.java

@@ -0,0 +1,13 @@
+package c;
+
+import a.A1;
+import b.B1;
+import b.nestedB.B2Kt;
+
+public class JavaC {
+    private void doStuff() {
+        C1 c1 = new C1();
+        B1 b1 = new B1();
+        B2Kt.bar(new A1());
+    }
+}