Introduce support for plugin-defined intrinsics in JVM IR backend:

Add intrinsic for kotlinx.serialization.serializer<T>() function.

Plugin intrinsic for old backend is removed because it is too hard
and unjustifiable to unify them.

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

@@ -55,6 +55,12 @@ public class SerializationIrBoxTestGenerated extends AbstractSerializationIrBoxT
         runTest("plugins/kotlinx-serialization/testData/boxIr/inlineClasses.kt");
     }
 
+    @Test
+    @TestMetadata("intrinsicsBox.kt")
+    public void testIntrinsicsBox() throws Exception {
+        runTest("plugins/kotlinx-serialization/testData/boxIr/intrinsicsBox.kt");
+    }
+
     @Test
     @TestMetadata("metaSerializable.kt")
     public void testMetaSerializable() throws Exception {