adb-remount-test: add /system/priv-app

In 4.19+ kernels not yet patched, /system/priv-app/<file> can
cause EPERM on fstat of the directory, resulting in failure to
access content.

Test: adb-remount-test.sh
Bug: 138649540
Change-Id: I96d1acb3cdb80824c9d2ebce415ea6e1253f9c5b
1 file changed