Remove toString implementation from Kotlin lambda base class since it uses unsupported reflection API

classlib/src/main/java/org/teavm/classlib/impl/JCLPlugin.java

@@ -109,6 +109,7 @@ public class JCLPlugin implements TeaVMPlugin {
 
         if (!isBootstrap()) {
             host.add(new ScalaHacks());
+            host.add(new KotlinHacks());
         }
 
         host.add(new NumericClassTransformer());

classlib/src/main/java/org/teavm/classlib/impl/KotlinHacks.java

@@ -0,0 +1,40 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  Licensed under the Apache License, Version 2.0 (the "License");
+ *  you may not use this file except in compliance with the License.
+ *  You may obtain a copy of the License at
+ *
+ *       http://www.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS,
+ *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ */
+package org.teavm.classlib.impl;
+
+import java.util.ArrayList;
+import java.util.List;
+import org.teavm.model.ClassHolder;
+import org.teavm.model.ClassHolderTransformer;
+import org.teavm.model.ClassHolderTransformerContext;
+import org.teavm.model.MethodHolder;
+
+public class KotlinHacks implements ClassHolderTransformer {
+    @Override
+    public void transformClass(ClassHolder cls, ClassHolderTransformerContext context) {
+        if (cls.getName().equals("kotlin.jvm.internal.Lambda")) {
+            List<MethodHolder> methodsToRemove = new ArrayList<>();
+            for (MethodHolder method : cls.getMethods()) {
+                if (method.getName().equals("toString")) {
+                    methodsToRemove.add(method);
+                }
+            }
+            for (MethodHolder method : methodsToRemove) {
+                cls.removeMethod(method);
+            }
+        }
+    }
+}