test/system: Silence SC2154

Otherwise https://www.shellcheck.net/ would complain:
  Line 33:
  assert [ ${#stderr_lines[@]} -eq 0 ]
           ^-----------------^ SC2154 (warning): stderr_lines is
                               referenced but not assigned.

See: https://www.shellcheck.net/wiki/SC2154

https://github.com/containers/toolbox/pull/1369

test/system/001-version.bats

@@ -30,5 +30,7 @@ setup() {
   assert_success
   assert_output --regexp '^toolbox version [0-9]+\.[0-9]+\.[0-9]+(\.[0-9]+)?$'
   assert [ ${#lines[@]} -eq 1 ]
+
+  # shellcheck disable=SC2154
   assert [ ${#stderr_lines[@]} -eq 0 ]
 }

test/system/102-list.bats

@@ -34,6 +34,8 @@ teardown() {
 
   assert_success
   assert [ ${#lines[@]} -eq 0 ]
+
+  # shellcheck disable=SC2154
   assert [ ${#stderr_lines[@]} -eq 0 ]
 }
 

test/system/104-run.bats

@@ -54,6 +54,8 @@ teardown() {
 
   assert_success
   assert [ ${#lines[@]} -eq 0 ]
+
+  # shellcheck disable=SC2154
   assert [ ${#stderr_lines[@]} -eq 0 ]
 }
 

test/system/107-rmi.bats

@@ -39,6 +39,8 @@ teardown() {
 
   assert_success
   assert [ ${#lines[@]} -eq 0 ]
+
+  # shellcheck disable=SC2154
   assert [ ${#stderr_lines[@]} -eq 0 ]
 
   num_of_images="$(list_images)"

test/system/108-completion.bats

@@ -29,6 +29,8 @@ setup() {
 
   assert_success
   assert [ ${#lines[@]} -gt 0 ]
+
+  # shellcheck disable=SC2154
   assert [ ${#stderr_lines[@]} -eq 0 ]
 }
 

test/system/libs/helpers.bash

@@ -236,7 +236,10 @@ function build_image_without_name() {
   assert_line --index 1 --partial "LABEL com.github.containers.toolbox=\"true\""
   assert_line --index 2 --partial "COMMIT"
   assert_line --index 3 --regexp "^--> [a-f0-9]{6,64}$"
+
+  # shellcheck disable=SC2154
   last=$((${#lines[@]}-1))
+
   assert_line --index "$last" --regexp "^[a-f0-9]{64}$"
 
   rm -f "$BATS_TEST_TMPDIR"/Containerfile
@@ -440,6 +443,7 @@ function container_started() {
     run "$PODMAN" logs "$container_name"
 
     # Look for last line of the container startup log
+    # shellcheck disable=SC2154
     if echo "$output" | grep "Listening to file system and ticker events"; then
       container_initialized=0
       break