testing: set up nightly run that runs fuzz tests

We have a couple of tests that use [Go fuzzing](https://go.dev/security/fuzz/) infrastructure:
```
pkg/storage/engine_key_test.go
338:func FuzzEngineKeysInvariants(f *testing.F) {

pkg/sql/sqlliveness/slstorage/sessionid_test.go
25:func FuzzSessionIDEncoding(f *testing.F) {
```

Fuzz tests only do something more interesting than regular tests when the `-fuzz` flag is used. We should set up a nightly run that does this.

Jira issue: CRDB-31052