[java decompiler] detecting Groovy synthetic constructor parameters

testData/src/pkg/TestGroovyClass.groovy

@@ -0,0 +1,13 @@
+package pkg
+
+import java.util.concurrent.Callable
+
+class TestGroovyClass {
+  static class Nested { }
+  class Inner { }
+
+  final Nested n = new Nested()
+  final Inner i = new Inner()
+  final Runnable r = { println("I'm runnable") }
+  final Callable<String> c = { "I'm callable" }
+}