FIR checker: warn useless as and is

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/neg/15.fir.kt

@@ -43,7 +43,7 @@ fun case_2(value: Any) {
 
 // TESTCASE NUMBER: 3
 fun case_3(value: String?) {
-    if (!value.isNullOrEmpty() is Boolean) {
+    if (<!USELESS_IS_CHECK!>!value.isNullOrEmpty() is Boolean<!>) {
         value<!UNSAFE_CALL!>.<!>length
     }
 }

compiler/tests-spec/testData/diagnostics/notLinked/contracts/analysis/smartcasts/pos/2.fir.kt

@@ -158,7 +158,7 @@ class case_10_class {
  * ISSUES: KT-26747
  */
 fun case_11(value_1: Any?, value_2: Any?, value_3: Any?) {
-    funWithReturnsAndInvertCondition(value_1 !is String || value_2 !is Number || value_3 !is Any?)
+    funWithReturnsAndInvertCondition(value_1 !is String || value_2 !is Number || <!USELESS_IS_CHECK!>value_3 !is Any?<!>)
     println(value_1<!UNNECESSARY_NOT_NULL_ASSERTION!>!!<!>.length)
     println(value_2<!UNNECESSARY_SAFE_CALL!>?.<!>toByte())
 }