Add toString() to Any, fix all tests

#KT-4517 Fixed

libraries/stdlib/test/CompareTest.kt

@@ -5,7 +5,7 @@ import kotlin.test.*
 import org.junit.Test
 
 class Item(val name: String, val rating: Int): Comparable<Item> {
-    fun toString() = "Item($name, $rating)"
+    override fun toString() = "Item($name, $rating)"
 
     public override fun compareTo(other: Item): Int {
         return compareBy(this, other, { rating }, { name })

libraries/stdlib/test/ListTest.kt

@@ -6,7 +6,7 @@ import org.junit.Test as test
 
 class ListTest {
 
-    test fun toString() {
+    test fun _toString() {
         val data = arrayList("foo", "bar")
         assertEquals("[foo, bar]", data.toString())
     }

libraries/stdlib/test/properties/PropertiesTest.kt

@@ -22,7 +22,7 @@ class Customer() : ChangeSupport() {
         $city = value
     }
 
-    fun toString() = "Customer($name, $city)"
+    override fun toString() = "Customer($name, $city)"
 }
 
 class MyChangeListener() : ChangeListener {

libraries/stdlib/test/regressions/kt1202.kt

@@ -33,7 +33,7 @@ class Failure(val message : String) : ParseResult<Nothing> {
 }
 
 open class Token(val text : String) {
-    fun toString() = text
+    override fun toString() = text
 }
 object LPAR : Token("(")
 object RPAR : Token(")")