Option to drop into 'recover' when running testJob throws an error

[mb706]

I want to be able to run testJob() and go into the debugger when an error occurs. Currently, testJob() ends up calling execJob.Experiment, which does this

https://github.com/mllg/batchtools/blob/1196047ed5115d54bde2923848c1f3ec11fda6d2/R/execJob.R#L36

This means I can not set options(error=recover) before running testJob() to get what I want. There should be some kind of option to override this, or to stop execJob from overwriting options here (realistically someone might want to have an 'error' option that is something else entirely).