Backend support for function expression

compiler/testData/codegen/boxWithStdlib/reflection/enclosing/functionExpressionInProperty.kt

@@ -0,0 +1,16 @@
+val property = fun () {}
+
+fun box(): String {
+    val javaClass = property.javaClass
+
+    val enclosingMethod = javaClass.getEnclosingMethod()
+    if (enclosingMethod != null) return "method: $enclosingMethod"
+
+    val enclosingClass = javaClass.getEnclosingClass()!!.getName()
+    if (!enclosingClass.startsWith("_DefaultPackage") || !enclosingClass.contains("functionExpressionInProperty")) return "enclosing class: $enclosingClass"
+
+    val declaringClass = javaClass.getDeclaringClass()
+    if (declaringClass != null) return "anonymous function has a declaring class: $declaringClass"
+
+    return "OK"
+}