Occasionally, the removal of GITHUB_WORKSPACE fails for self-hosted runners
because one of the subdirectories is not empty. This is likely due to another
process occupying the directory at the time.
Implementing a secondary cleanup resolves this issue.
This commit focuses on the implementation for the secondary cleanup.
Fixes: #9317
Signed-off-by: Hyounggyu Choi <Hyounggyu.Choi@ibm.com>