[JS IR] Type operator call pureness

compiler/ir/backend.common/src/org/jetbrains/kotlin/backend/common/ir/IrUtils.kt

@@ -661,6 +661,12 @@ fun IrExpression?.isPure(
                 if (valueDeclaration is IrVariable) !valueDeclaration.isVar
                 else true
             }
+            is IrTypeOperatorCall ->
+                (
+                        operator == IrTypeOperator.INSTANCEOF ||
+                                operator == IrTypeOperator.REINTERPRET_CAST ||
+                                operator == IrTypeOperator.NOT_INSTANCEOF
+                        ) && argument.isPure(anyVariable, checkFields, context)
             is IrCall -> if (context?.isSideEffectFree(this) == true) {
                 for (i in 0 until valueArgumentsCount) {
                     val valueArgument = getValueArgument(i)

compiler/ir/backend.js/src/org/jetbrains/kotlin/ir/backend/js/JsIrBackendContext.kt

@@ -61,7 +61,8 @@ class JsIrBackendContext(
 
     override fun isSideEffectFree(call: IrCall): Boolean =
         call.symbol in intrinsics.primitiveToLiteralConstructor.values ||
-                call.symbol == intrinsics.arrayLiteral
+                call.symbol == intrinsics.arrayLiteral ||
+                call.symbol == intrinsics.arrayConcat
 
     val devMode = configuration[JSConfigurationKeys.DEVELOPER_MODE] ?: false
     val errorPolicy = configuration[JSConfigurationKeys.ERROR_TOLERANCE_POLICY] ?: ErrorTolerancePolicy.DEFAULT