"Find Usages": add tests for Kotlin usages of Java declarations

idea/testData/findUsages/java/findJavaClassUsages/JKClassMethodsUsages.1.kt

@@ -0,0 +1,38 @@
+public class X(bar: String? = A.BAR): A() {
+    var next: A? = A()
+    val myBar: String? = A.BAR
+
+    {
+        A.BAR = ""
+        A.foos()
+    }
+
+    fun foo(a: A) {
+        val aa: A = a
+        aa.bar = ""
+    }
+
+    fun getNext(): A? {
+        return next
+    }
+
+    public override fun foo() {
+        super<A>.foo()
+    }
+
+    class object: A() {
+
+    }
+}
+
+object O: A() {
+
+}
+
+fun X.bar(a: A = A()) {
+
+}
+
+fun Any.toA(): A? {
+    return if (this is A) this as A else null
+}