Don't shared oem-defined libs to vendor apks

OEM-defined libs in /system/etc/public.libraries-<companyname>.txt files
are not available to apks in the vendor partition, otherwise we are
allowing vendor -> system dependency, which is a Treble violation.

Bug: 71561542
Test: mm -j under system/core/libnativeloader/test and runtest.sh
the four libs (lib[foo|bar].[oem1|oem2].so are all loaded in
android.app.test.system app but not in android.app.test.vendor app

Change-Id: Ie5d9160ae4dc2a64beb6507602ee5a1db6518875
diff --git a/libnativeloader/test/runtest.sh b/libnativeloader/test/runtest.sh
new file mode 100755
index 0000000..40beb5b
--- /dev/null
+++ b/libnativeloader/test/runtest.sh
@@ -0,0 +1,11 @@
+#!/bin/bash
+adb root
+adb remount
+adb sync
+adb shell stop
+adb shell start
+sleep 5 # wait until device reboots
+adb logcat -c;
+adb shell am start -n android.test.app.system/android.test.app.TestActivity
+adb shell am start -n android.test.app.vendor/android.test.app.TestActivity
+adb logcat | grep android.test.app