This moves the distribution definitions into a maintainable hujson file
instead of just existing as constants in `distros.go`. Comments are
maintained from the inline definitions.
This uses jennifer[1] for hygenic source tree creation. This allows us
to generate a unique top-level test for each VM run. This should
hopefully help make the output of `go test` easier to read.
This also separates each test out into its own top-level test so that we
can better track the time that each distro takes. I really wish there
was a way to have the `test_codegen.go` file _always_ run as a part of
the compile process instead of having to rely on people remembering to
run `go generate`, but I am limited by my tools.
This will let us remove the `-distro-regex` flag and use `go test -run`
to pick which distros are run.
Signed-off-by: Christine Dodrill <xe@tailscale.com>
Christine Dodrill