Automatic merge from submit-queue (batch tested with PRs 59310, 60424, 60308, 60436, 60020). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Fix potential issues and bugs in hack/lib/*.sh scripts using shellcheck

**What this PR does / why we need it**:

This PR is continuing the work for cleaning up the shell scripts using shellcheck and manual inspection. The plan is to make the scripts more robust in case for unexpected input and also to fix potential bugs.

**Which issue(s) this PR fixes** *(optional, in `fixes #<issue number>(, fixes #<issue_number>, ...)` format, will close the issue(s) when PR gets merged)*:
Fixes #

**Special notes for your reviewer**:

The changes are for scripts in `hack/lib/` directory, and as library scripts are used from multiple places. It is not trivial to see all possible places from where the scripts are accessed, so careful review is needed. I tried to make sure that the changes would be compatible for older bash versions too.

**Release note**:

```release-note
NONE
```