fs_mgr: overlayfs: test: skip apex mounts

Strip out /dev/block/loop* devices to filter out apex mounts.  Deal
with scale of skip_administrative_mounts function to make for easier
maintenance.

Test: adb-remount-test.sh
Bug: 109821005
Bug: 112455435
Change-Id: Ic7382a613db8f3ac7cdc10721194042378d136b9

fs_mgr/tests/adb-remount-test.sh

@@ -176,11 +176,15 @@ check_eq() {
     die "${@}"
 }
 
-[ "USAGE: skip_administrative_mounts
+[ "USAGE: skip_administrative_mounts < /proc/mounts
 
-Filters out all administrative (eg: sysfs) mounts" ]
+Filters out all administrative (eg: sysfs) mounts uninteresting to the test" ]
 skip_administrative_mounts() {
-  grep -v -e "^\(overlay\|tmpfs\|none\|sysfs\|proc\|selinuxfs\|debugfs\|bpf\|cg2_bpf\|pstore\|tracefs\|adb\|mtp\|ptp\|devpts\|/data/media\) " -e " /\(cache\|mnt/scratch\|mnt/vendor/persist\|metadata\|data\) "
+  grep -v \
+    -e "^\(overlay\|tmpfs\|none\|sysfs\|proc\|selinuxfs\|debugfs\) " \
+    -e "^\(bpf\|cg2_bpf\|pstore\|tracefs\|adb\|mtp\|ptp\|devpts\) " \
+    -e "^\(/data/media\|/dev/block/loop[0-9]*\) " \
+    -e " /\(cache\|mnt/scratch\|mnt/vendor/persist\|metadata\|data\) "
 }
 
 if [ X"-s" = X"${1}" -a -n "${2}" ]; then