tmt: Fix stale loop partition state in multi-device ESP test

The three-devices-partial-ESP scenario fails with "No device found for
/dev/loop1p1" because the dual-ESP test's cleanup leaves stale kernel
partition nodes and LVM device registrations.

The prior cleanup called `pvremove -f $loop` on the loop device itself
(e.g. /dev/loop0) instead of on the partitions where PVs actually live
(e.g. /dev/loop0p2), making it a no-op.  After `losetup -d`, the
kernel retained busy partition nodes.  When the next test reused the
loop device with a different partition layout, `partx -u` tried to
atomically reconcile old and new partitions — but could not remove the
busy stale partition #2, so it aborted entirely without adding the new
partition #1.

Fix both cleanup and setup:

Cleanup:
- pvremove on actual partition devices (p1/p2/p3), not the loop device
- wipefs -a on each partition to clear signatures holding references
- udevadm settle to let udev finish processing
- partx -d to remove kernel partition entries before losetup -d
- Remove /etc/lvm/devices/system.devices to clear stale device IDs

Setup (setup_disk_with_partitions, setup_disk_with_root):
- Replace `partx -u` with `partx -d` (ignore errors) then `partx -a`,
  so a stuck stale partition does not block adding new ones
- Replace `sleep 1sec` with `udevadm settle` for reliable synchronization

Co-Authored-By: Claude Opus 4.6
Signed-off-by: Pragyan Poudyal <pragyanpoudyal41999@gmail.com>

Author: Johan-Liebert1

tmt/tests/booted/test-multi-device-esp.nu

@@ -45,13 +45,23 @@ def cleanup [vg_name: string, loops: list<string>, mountpoint: string] {
     do { vgchange -an $vg_name } | complete | ignore
     do { vgremove -f $vg_name } | complete | ignore
 
-    # Remove PVs and detach loop devices
+    # Remove PVs from partitions and detach loop devices
     for loop in $loops {
         if ($loop | path exists) {
-            do { pvremove -f $loop } | complete | ignore
+            for i in [1, 2, 3] {
+                let part = $"($loop)p($i)"
+                if ($part | path exists) {
+                    do { pvremove -f $part } | complete | ignore
+                    do { wipefs -a $part } | complete | ignore
+                }
+            }
+            do { udevadm settle } | complete | ignore
+            do { partx -d $loop } | complete | ignore
             do { losetup -d $loop } | complete | ignore
         }
     }
+
+    rm -f /etc/lvm/devices/system.devices
 }
 
 # Create a disk with GPT, optional ESP, and LVM partition
@@ -72,19 +82,21 @@ def setup_disk_with_partitions [
         # GPT with ESP (512MB) + LVM partition
         $"label: gpt\nsize=512M, type=($ESP_TYPE)\ntype=($LVM_TYPE)\n" | sfdisk $loop
 
-        # Reload partition table (partx is part of util-linux)
-        partx -u $loop
-        sleep 1sec
+        # Remove stale partition entries then add new ones; -d may fail
+        # for busy partitions from a prior test, but -a still succeeds
+        do { partx -d $loop } | complete | ignore
+        partx -av $loop
+        udevadm settle
 
         # Format ESP
         mkfs.vfat -F 32 $"($loop)p1"
     } else {
         # GPT with only LVM partition (full disk)
         $"label: gpt\ntype=($LVM_TYPE)\n" | sfdisk $loop
 
-        # Reload partition table (partx is part of util-linux)
-        partx -u $loop
-        sleep 1sec
+        do { partx -d $loop } | complete | ignore
+        partx -av $loop
+        udevadm settle
     }
 
     $loop
@@ -101,8 +113,9 @@ def setup_disk_with_root [
 
     # GPT with ESP (512MB) + root partition
     $"label: gpt\nsize=512M, type=($ESP_TYPE)\ntype=($ROOT_TYPE)\n" | sfdisk $loop
-    partx -u $loop
-    sleep 1sec
+    do { partx -d $loop } | complete | ignore
+    partx -av $loop
+    udevadm settle
 
     mkfs.vfat -F 32 $"($loop)p1"
     mkfs.ext4 -q $"($loop)p2"