adb-remount-test.sh: Filter out administrative mount: securityfs

securityfs /sys/kernel/security securityfs rw,relatime 0 0

is causing the noatime check in adb-remount-test.sh to fail.

Bug: 165925766
Test: Create an aosp_cf_x86_phone-userdebug AVD && adb-remount-test.sh
Test: Use DSU to install GSI on the AVD && adb-remount-test.sh
Change-Id: Ibae0d4bbbbc78fb74f4ad82f2313251598c77f72
diff --git a/fs_mgr/tests/adb-remount-test.sh b/fs_mgr/tests/adb-remount-test.sh
index f5bbe35..2433833 100755
--- a/fs_mgr/tests/adb-remount-test.sh
+++ b/fs_mgr/tests/adb-remount-test.sh
@@ -740,7 +740,7 @@
   grep -v \
     -e "^\(overlay\|tmpfs\|none\|sysfs\|proc\|selinuxfs\|debugfs\|bpf\) " \
     -e "^\(binfmt_misc\|cg2_bpf\|pstore\|tracefs\|adb\|mtp\|ptp\|devpts\) " \
-    -e "^\(ramdumpfs\|binder\|/sys/kernel/debug\) " \
+    -e "^\(ramdumpfs\|binder\|/sys/kernel/debug\|securityfs\) " \
     -e " functionfs " \
     -e "^\(/data/media\|/dev/block/loop[0-9]*\) " \
     -e "^rootfs / rootfs rw," \