Cloning related JDK not working

[wmdietl]

PR #1590 adds a test case for a related JDK change.
Both are in branches with the same name, but the correct JDK branch isn't cloned.

CI shows:

+ DEFAULT_BRANCH_NAME=master
+ '[' '' = --debug ']'
+ '[' -n '' ']'
+ '[' -n '' ']'
+ '[' '' = true ']'
+ '[' -n '' ']'
+ '[' -n pattern-regexes ']'
+ '[' '' = --debug ']'
+ CI_IS_PULL_REQUEST=true
+ CI_BRANCH_NAME=pattern-regexes
++ git rev-parse remotes/origin/master
fatal: ambiguous argument 'remotes/origin/master': unknown revision or path not in the working tree.
Use '--' to separate paths from revisions, like this:
'git <command> [<revision>...] -- [<file>...]'
+ CI_COMMIT_RANGE_START=remotes/origin/master
git-clone-related: About to run: git clone -q -b master -q --single-branch --depth 1 https://github.com/eisop/jdk.git ../jdk
git-clone-related: ../jdk is at 9d40ad20e43217893af1fa818edbe45ec8d11f4e
++ '[' -z '' ']'
++ TERM=dumb
++ timeout 300 ./gradlew --write-verification-metadata sha256 help --dry-run --quiet
:help SKIPPED
+++ pwd
++ echo Exiting checker/bin-devel/clone-related.sh in /home/runner/work/checker-framework/checker-framework

This used to work and might have been broken by pulling in upstream changes here https://github.com/eisop-plume-lib/git-scripts/pull/6/files#diff-9733d361398b20bb970e8a8112333eae2bf93d70146428d0e63dd9896c9aa30b