Update int.cloudbuild.yaml

Author: apeabody

build/int.cloudbuild.yaml

@@ -30,12 +30,12 @@ steps:
       git fetch --unshallow
       git diff origin/${_BASE_BRANCH} --name-only > _changed_files
       sed 's:[^/]*$::' _changed_files > _changed_folders
-      sort -u _changed_folders
+      sort -u -o _changed_folders{,}
       echo Changed folders:
       cat _changed_folders
 
       # Do not prune if changing tests themselves
-      _INFRA_FOLDERS="build test .github"
+      _INFRA_FOLDERS="build test/ .github/"
       for d in _changed_folders; do
         if [[ "${_INFRA_FOLDERS}" =~ "$d" ]]; then
           echo "Infrastructure folders have changed; no tests will be pruned."