* Replace use of `testChdir` with `t.Chdir`
* Update tests to use temporary directories with copied content, instead of using directories in the repo directly.
* Remove stacks copy of testChdir function
This has been replaced with t.Chdir from the standard library
* Replace remaining simple usage of testChdir
* Update guidance for using `tempWorkingDir`
* Replace use of testChdir in a function reused in a single test
* Update comments to no longer recommend using testChdir
* Remove testChdir function!