Reland "libbinder: remove __ANDROID_APEX__ stability diff"

Since the product partition is using __ANDROID_VNDK__, we can't remove
the __ANDROID_APEX__ check from the NDK header.

This reverts commit 15b7029849a1c59ecb54961fa7417ee0611408a0.

Reason for revert: reland b/179906909

Fixes: 179906909
Test: the following, which was failing before w/ stability error
mmma packages/modules/Gki
adb install --staged-ready-timeout 600000\
   out/host/linux-x86/testcases/GkiInstallTest/com.android.gki.kmi_5_10_android12_0_test_high.apex

Change-Id: I189b5c07ffd767fa46c59fd8828ba4f59b31f095
diff --git a/libs/binder/Stability.cpp b/libs/binder/Stability.cpp
index 339c538..b56e09f 100644
--- a/libs/binder/Stability.cpp
+++ b/libs/binder/Stability.cpp
@@ -76,18 +76,12 @@
 }
 
 Stability::Level Stability::getLocalLevel() {
+#ifdef __ANDROID_APEX__
+#error APEX can't use libbinder (must use libbinder_ndk)
+#endif
+
 #ifdef __ANDROID_VNDK__
-    #ifdef __ANDROID_APEX__
-        // TODO(b/142684679) avoid use_vendor on system APEXes
-        #if !defined(__ANDROID_APEX_COM_ANDROID_MEDIA_SWCODEC__) \
-            && !defined(__ANDROID_APEX_TEST_COM_ANDROID_MEDIA_SWCODEC__)
-        #error VNDK + APEX only defined for com.android.media.swcodec
-        #endif
-        // TODO(b/142684679) avoid use_vendor on system APEXes
-        return Level::SYSTEM;
-    #else
-        return Level::VENDOR;
-    #endif
+    return Level::VENDOR;
 #else
     // TODO(b/139325195): split up stability levels for system/APEX.
     return Level::SYSTEM;