find usages of Kotlin methods in Java code (KT-1819)

#KT-1819 fixed

idea/testData/findUsages/findMethodUsages/Client.java

@@ -0,0 +1,8 @@
+import testing.*;
+
+class Client {
+    public void foo() {
+        Server server = new Server();
+        server.processRequest();
+    }
+}

idea/testData/findUsages/findMethodUsages/Server.kt

@@ -0,0 +1,5 @@
+package testing;
+
+public class Server() {
+    public fun <caret>processRequest() = "foo"
+}