Add toString() to Any, fix all tests

#KT-4517 Fixed

compiler/testData/psi/recovery/MissingCommaInConstructorValueParameterList.kt

@@ -1,3 +1,3 @@
 class Test(private val a: Int b: Int private val c: Int) {
-    fun toString() = "$a $c"
+    override fun toString() = "$a $c"
 }

compiler/testData/psi/recovery/MissingCommaInConstructorValueParameterList.txt

@@ -53,6 +53,9 @@ JetFile: MissingCommaInConstructorValueParameterList.kt
       PsiElement(LBRACE)('{')
       PsiWhiteSpace('\n    ')
       FUN
+        MODIFIER_LIST
+          PsiElement(override)('override')
+        PsiWhiteSpace(' ')
         PsiElement(fun)('fun')
         PsiWhiteSpace(' ')
         PsiElement(IDENTIFIER)('toString')