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

compiler/testData/diagnostics/tests/regressions/kt1639-JFrame.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FULL_JDK
 // SKIP_TXT
 
@@ -7,6 +8,6 @@ import javax.swing.JFrame
 
 class KFrame() : JFrame() {
     init {
-        val <!UNUSED_VARIABLE!>x<!> = this.rootPaneCheckingEnabled // make sure field is visible
+        val x = this.rootPaneCheckingEnabled // make sure field is visible
     }
 }