[JS IR] Fix JS code diagnostics tests according to new KLIB checks

^KT-62425

compiler/testData/diagnostics/testsWithJsStdLibAndBackendCompilation/jsCode/deleteOperation.kt

@@ -1,3 +1,8 @@
+// FIR_DIFFERENCE
+// The diagnostic cannot be implemented with the FIR frontend checker because it requires constant evaluation over FIR.
+// The diagnostic is implemented as a klib check over IR.
+
+// ERROR_POLICY: SEMANTIC
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 fun foo(x: Any) {
@@ -5,4 +10,4 @@ fun foo(x: Any) {
     js("delete x['bar'];")
     js("delete x.baz<!JSCODE_ERROR!>()<!>;")
     js("delete <!JSCODE_ERROR!>this<!>;")
-}
+}