Use CodegenContext to determine outer class & enclosing method

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

@@ -0,0 +1,25 @@
+class O {
+    class object {
+        // Currently we consider <clinit> in class O as the enclosing method of this lambda,
+        // so we write outer class = O and enclosing method = null
+        val f = {}
+    }
+}
+
+fun box(): String {
+    val javaClass = O.f.javaClass
+
+    val enclosingMethod = javaClass.getEnclosingMethod()
+    if (enclosingMethod != null) return "method: $enclosingMethod"
+
+    val enclosingConstructor = javaClass.getEnclosingConstructor()
+    if (enclosingConstructor != null) return "constructor: $enclosingConstructor"
+
+    val enclosingClass = javaClass.getEnclosingClass()
+    if (enclosingClass?.getName() != "O") return "enclosing class: $enclosingClass"
+
+    val declaringClass = javaClass.getDeclaringClass()
+    if (declaringClass != null) return "anonymous function has a declaring class: $declaringClass"
+
+    return "OK"
+}