[Test] Disable UNUSED_* diagnostics in tests which are not belong to contolFlowAnalysis suite

compiler/testData/diagnostics/tests/inference/regressions/kt3496.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_VARIABLE
 // KT-3496 Type inference bug on y[""]
 
@@ -5,5 +6,5 @@ class B<T> {
     fun <S> x (y: B<Iterable<S>>) {
         val z: S = y[""] // does not work with [], but works with .get()
     }
-    operator fun <S> get(<!UNUSED_PARAMETER!>s<!> : String): S = throw Exception()
-}
+    operator fun <S> get(s : String): S = throw Exception()
+}