[KxSerialization] Fix NPE when accessing delegated property

Kotlin 1.7.20 added optimizations for delegated properties on the JVM,
which broke serialization for optimized properties. Commit bfeff81
tried to fix that, but broke non-optimized delegated properties. This
commit restores correct serialization for optimized and non-optimized
properties, also ensuring that it only affects the JVM target.

 #KT-58954 Fixed
 #KT-59113 Fixed

plugins/kotlinx-serialization/tests-gen/org/jetbrains/kotlinx/serialization/runners/SerializationIrJsBoxTestGenerated.java

@@ -31,6 +31,12 @@ public class SerializationIrJsBoxTestGenerated extends AbstractSerializationIrJs
         runTest("plugins/kotlinx-serialization/testData/boxIr/constValInSerialName.kt");
     }
 
+    @Test
+    @TestMetadata("delegatedProperty.kt")
+    public void testDelegatedProperty() throws Exception {
+        runTest("plugins/kotlinx-serialization/testData/boxIr/delegatedProperty.kt");
+    }
+
     @Test
     @TestMetadata("excludedFromExport.kt")
     public void testExcludedFromExport() throws Exception {