chore(jenkins): clean up custom workspace directories

Author: lprimak

.jenkins.groovy

@@ -201,6 +201,20 @@ Check console output at "<a href="${env.BUILD_URL}">${env.JOB_NAME} [${env.BRANC
                         // Cleanup the build directory if the build was successful
                         // (in this case we probably don't have to do any post-build analysis)
                         cleanBeforeCheckout()
+                        stage('Prune old workspaces') {
+                            when {
+                                expression { MATRIX_JDK == latestSupportedJDK }
+                            }
+                            steps {
+                                sh '''
+                                    set -eu
+                                    base_dir="workspace/${JOB_NAME}/MatrixCheckout"
+                                    if [ -d "$base_dir" ]; then
+                                       find "$base_dir" -mindepth 1 -maxdepth 1 -type d -mtime +30 -exec rm -rf {} +
+                                    fi
+                                '''
+                            }
+                        }
                         script {
                             if (deployableBranch
                                     && (currentBuild.previousBuild != null) && (currentBuild.previousBuild.result != 'SUCCESS')) {