Don't use backing fields for properties generated from macros

Thus don't require running initializer for these.

Interop/StubGenerator/src/main/kotlin/org/jetbrains/kotlin/native/interop/gen/jvm/StubGenerator.kt

@@ -776,7 +776,7 @@ class StubGenerator(
         // Also it provokes constant propagation which can reduce binary compatibility
         // when replacing interop stubs without recompiling the application.
 
-        out("val ${constant.name.asSimpleName()}: $kotlinType = $literal")
+        out("val ${constant.name.asSimpleName()}: $kotlinType get() = $literal")
     }
 
     private fun generateStubs(): List<KotlinStub> {