Add some new tests on functions and extension functions

compiler/testData/codegen/box/functions/invoke/castFunctionToExtension.kt

@@ -0,0 +1,11 @@
+fun box(): String {
+    val f = fun (s: String): String = s
+    val g = f as String.() -> String
+    if ("OK".g() != "OK") return "Fail 1"
+
+    val h = fun String.(): String = this
+    val i = h as (String) -> String
+    if (i("OK") != "OK") return "Fail 2"
+
+    return "OK"
+}

compiler/testData/codegen/boxWithJava/reflection/functionReferenceErasedToKFunction/J.java

@@ -0,0 +1,10 @@
+import kotlin.jvm.functions.Function2;
+import kotlin.reflect.KMemberFunction;
+
+public class J {
+    public static String go() {
+        KMemberFunction<K, String> fun = K.Companion.getRef();
+        Object result = ((Function2) fun).invoke(new K(), "KO");
+        return (String) result;
+    }
+}

compiler/testData/codegen/boxWithJava/reflection/functionReferenceErasedToKFunction/K.kt

@@ -0,0 +1,13 @@
+class K {
+    fun reverse(s: String): String {
+        return s.reverse()
+    }
+
+    companion object {
+        fun getRef() = K::reverse
+    }
+}
+
+fun box(): String {
+    return J.go()
+}

compiler/testData/codegen/boxWithStdlib/callableReference/function/listOfStringsMapLength.kt

@@ -0,0 +1,2 @@
+fun box(): String =
+        if (listOf("abc", "de", "f").map(String::length) == listOf(3, 2, 1)) "OK" else "Fail"