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

compiler/testData/diagnostics/tests/varargs/NilaryVsVararg.kt

@@ -1,10 +1,11 @@
+// FIR_IDENTICAL
 fun foo0() : String = "noarg"
 
-fun foo0(vararg <!UNUSED_PARAMETER!>t<!> : Int) : String = "vararg"
+fun foo0(vararg t : Int) : String = "vararg"
 
 fun test0() {
     foo0()
     foo0(1)
     val a = IntArray(0)
     foo0(*a)
-}
+}