Correctly count regular members of Dynamic (#1632)

Previously, `VmDynamic.isHiddenOrLocalProperty` didn't correctly
identify locals whose cache key is an `ObjectMember` instead of an
`Identifier`, causing `VmDynamic. getRegularMemberCount` to return an
incorrect value. This caused some renderers to produce incorrect output.

Resolves #1631

pkl-core/src/main/java/org/pkl/core/runtime/VmDynamic.java

@@ -158,7 +158,8 @@ public final class VmDynamic extends VmObject {
   }
 
   private boolean isHiddenOrLocalProperty(Object key) {
-    return key instanceof Identifier
+    return key instanceof ObjectMember member && member.isLocal()
-        && (key == Identifier.DEFAULT || ((Identifier) key).isLocalProp());
+        || key instanceof Identifier identifier
+            && (key == Identifier.DEFAULT || identifier.isLocalProp());
   }
 }

pkl-core/src/test/kotlin/org/pkl/core/EvaluatorTest.kt

@@ -635,7 +635,7 @@ class EvaluatorTest {
   }
 
   @Test
-  fun `nested pkl-binary rendiring produces correct results`() {
+  fun `nested pkl-binary rendering produces correct results`() {
     val evaluator =
       with(EvaluatorBuilder.preconfigured()) {
         allowedResources.add(Pattern.compile("b64:"))
@@ -696,6 +696,48 @@ class EvaluatorTest {
     }
   }
 
+  @Test
+  fun `objects with object locals are encoded correctly`() {
+    val data =
+      evaluator.evaluateOutputBytes(
+        text(
+          """
+          import "pkl:pklbinary"
+
+          dynamic: Dynamic = new {
+            local foo = new Test {}
+            bar = foo
+          }
+          listing: Listing = new {
+            local foo = new Test {}
+            foo
+          }
+          mapping: Mapping = new {
+            local foo = new Test {}
+            ["bar"] = foo
+          }
+          `class`: MyClass = new {
+            local foo = new Test {}
+            bar = foo
+          }
+
+          class MyClass {
+            bar: Test
+          }
+
+          class Test
+
+          output {
+            renderer = new pklbinary.Renderer {}
+          }
+          """
+            .trimIndent()
+        )
+      )
+
+    assertThatCode { PklBinaryDecoder.decode(data) }.doesNotThrowAnyException()
+  }
+
   @Test
   fun `power assertions work with test facts with unavailable source section`() {
     val evaluator =