[FE 1.0] Report USELESS_IS_CHECK if is expression is always false

^KT-47684 Fixed

compiler/tests-spec/testData/diagnostics/notLinked/dfa/pos/68.kt

@@ -47,7 +47,7 @@ fun case_4(x: Any?) {
 
 // TESTCASE NUMBER: 5
 fun case_5(x: Any?) {
-    if (x as Nothing? is Nothing) {
+    if (<!USELESS_IS_CHECK!>x as Nothing? is Nothing<!>) {
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!>
         <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Any? & kotlin.Nothing?")!>x<!><!UNSAFE_CALL!>.<!><!MISSING_DEPENDENCY_CLASS!>inv<!>()
     }