Fix: determine whether the destination path already exists before clone

If directory ${GOPATH}/src/github.com/google/licenseclassifier exists and
is not empty we should skip clone again or will cause an error.

Related Issue: tektoncd/pipeline#5193

Signed-off-by: yuzhipeng <yuzp1996@qq.com>

tekton/images/test-runner/entrypoint.sh

@@ -17,8 +17,14 @@ set -o errexit
 set -o nounset
 set -o pipefail
 
-# Workaround for https://github.com/google/licenseclassifier/issues/20
-git clone https://github.com/google/licenseclassifier ${GOPATH}/src/github.com/google/licenseclassifier
+DIR="${GOPATH}/src/github.com/google/licenseclassifier"
+
+if [ "$(ls -A $DIR)" ]; then
+    echo "$DIR is not Empty. Skip clone..."
+else
+    # Workaround for https://github.com/google/licenseclassifier/issues/20
+    git clone https://github.com/google/licenseclassifier $DIR
+fi
 
 # actually start bootstrap and the job, under the runner (which handles dind etc.)
 /usr/local/bin/runner.sh "$@"