RHOAIENG-20088: chore(ci/check-params-env.sh|check-runtime-images.sh)

Assure that when the expected image size variable isn't defined or is
zero, then the execution fails with some decent message.

Author: jstourac

ci/check-params-env.sh

@@ -249,6 +249,11 @@ function check_image_variable_matches_name_and_commitref_and_size() {
     }
 
     # Check the size change constraints now
+    if test -z "${expected_img_size}" || test "${expected_img_size}" -eq 0; then
+        echo "Expected image size is undefined or empty, please check the pre-defined values!"
+        return 1
+    fi
+
     # 1. Percentual size change
     percent_change=$((100 * actual_img_size / expected_img_size - 100))
     abs_percent_change=${percent_change#-*}

ci/check-runtime-images.sh

@@ -58,6 +58,11 @@ function check_image_size() {
     esac
 
     # Check the size change constraints now
+    if test -z "${expected_img_size}" || test "${expected_img_size}" -eq 0; then
+        echo "Expected image size is undefined or empty, please check the pre-defined values!"
+        return 1
+    fi
+
     # 1. Percentual size change
     percent_change=$((100 * actual_img_size / expected_img_size - 100))
     abs_percent_change=${percent_change#-*}