libbinder: Consider VNDK_APEX as vendor stable

VNDK APEX is supposed to be used by vendor modules. So libbinder in VNDK
APEX should be treated as vendor.

Bug: 142582178
Test: device with current vndk boots successfully
Change-Id: Iba56a658dc73b6735feee055790b3e9d37a65ca6
diff --git a/libs/binder/Parcel.cpp b/libs/binder/Parcel.cpp
index e5c7d74..32e06cd 100644
--- a/libs/binder/Parcel.cpp
+++ b/libs/binder/Parcel.cpp
@@ -509,7 +509,7 @@
     }
 }
 
-#if defined(__ANDROID_VNDK__) && !defined(__ANDROID_APEX__)
+#if defined(__ANDROID_APEX_COM_ANDROID_VNDK_CURRENT__) || (defined(__ANDROID_VNDK__) && !defined(__ANDROID_APEX__))
 constexpr int32_t kHeader = B_PACK_CHARS('V', 'N', 'D', 'R');
 #else
 constexpr int32_t kHeader = B_PACK_CHARS('S', 'Y', 'S', 'T');