cannot check out main branch, filename too long

Can not check out the full default branch: git clone succeeds but errors out with `fatal: unable to checkout working tree`, because `File name too long`. This is on an Ubuntu-20.04 virtual machine with ecryptfs on top of ext4. Occurred on 2023-08-31 around 10:35am EDT. May be related to the filename length bug reported for Windows that was closed in April, #101116.

```
% git clone git@github.com:cockroachdb/cockroach cockroach.git
Cloning into 'cockroach.git'...
remote: Enumerating objects: 1061992, done.
remote: Counting objects: 100% (123/123), done.
remote: Compressing objects: 100% (107/107), done.
remote: Total 1061992 (delta 61), reused 44 (delta 16), pack-reused 1061869
Receiving objects: 100% (1061992/1061992), 1.36 GiB | 3.64 MiB/s, done.
Resolving deltas: 100% (847547/847547), done.
error: unable to create file pkg/ccl/backupccl/testdata/restore_old_versions/cluster/22.2.0/2022/12/22-030544.02/progress/BACKUP-CHECKPOINT-13cdcfcdcdd2cecdd2cdcddfcfccc5cfcac5cbcbd1cfc7cdc9cec8c6ccc8dfd4cfcfcfcfdfaaabbcdf92c2d4cecdcad1cfcacfc6cac6ccc8c6fffe-CHECKSUM: File name too long
error: unable to create file pkg/ccl/backupccl/testdata/restore_old_versions/cluster/22.2.0/2022/12/22-030544.02/progress/BACKUP-CHECKPOINT-13cdcfcdcdd2cecdd2cdcddfcfccc5cfcac5cbcbd1cfc9cacdcdcbcac7cadfd4cfcfcfcfdfaaabbcdf92c2d4cecdcad1cfcccccac9c9cfcdc8fffe-CHECKSUM: File name too long
Updating files: 100% (15640/15640), done.
fatal: unable to checkout working tree
warning: Clone succeeded, but checkout failed.
You can inspect what was checked out with 'git status'
and retry with 'git restore --source=HEAD :/'
```
Cleaning up the leftover files with `git checkout -f` shows
```
% git status
pkg/ccl/backupccl/testdata/restore_old_versions/cluster/22.2.0/2022/12/22-030544.02/progress/BACKUP-CHECKPOINT-13cdcfcdcdd2cecdd2cdcddfcfccc5cfcac5cbcbd1cfc7cdc9cec8c6ccc8dfd4cfcfcfcfdfaaabbcdf92c2d4cecdcad1cfcacfc6cac6ccc8c6fffe-CHECKSUM: File name too long
pkg/ccl/backupccl/testdata/restore_old_versions/cluster/22.2.0/2022/12/22-030544.02/progress/BACKUP-CHECKPOINT-13cdcfcdcdd2cecdd2cdcddfcfccc5cfcac5cbcbd1cfc9cacdcdcbcac7cadfd4cfcfcfcfdfaaabbcdf92c2d4cecdcad1cfcccccac9c9cfcdc8fffe-CHECKSUM: File name too long
On branch master
Your branch is up to date with 'origin/master'.
```

Jira issue: CRDB-31108