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

compiler/testData/diagnostics/tests/callableReference/resolve/kt12338.fir.kt

@@ -1,9 +0,0 @@
-// KT-12338 Compiler error ERROR: Rewrite at slice LEXICAL_SCOPE key: REFERENCE_EXPRESSION with when and function references
-
-fun a() { }
-
-fun test() {
-    when {
-        true -> ::a
-    }
-}

compiler/testData/diagnostics/tests/callableReference/resolve/kt12338.kt

@@ -1,9 +1,10 @@
+// FIR_IDENTICAL
 // KT-12338 Compiler error ERROR: Rewrite at slice LEXICAL_SCOPE key: REFERENCE_EXPRESSION with when and function references
 
 fun a() { }
 
 fun test() {
     when {
-        true -> <!UNUSED_EXPRESSION!>::a<!>
+        true -> ::a
     }
 }