Delete Hashable, pull up its members to Any

Extensions on nullable types remain in Library.kt

 #KT-1741 Obsolete
 #KT-2805 Obsolete
 #KT-1365 Fixed
 #KT-4517 In Progress

idea/testData/quickfix/changeSignature/beforeAddParameterNotAvailableForBuiltins.kt

@@ -1,5 +1,5 @@
 // "class org.jetbrains.jet.plugin.quickfix.AddFunctionParametersFix" "false"
-// ERROR: Too many arguments for public fun jet.Any?.equals(other: jet.Any?): jet.Boolean defined in jet
+// ERROR: Too many arguments for public open fun equals(other: jet.Any?): jet.Boolean defined in jet.Any
 
 fun f(d: Any) {
     d.equals("a", <caret>"b")