.github: Include initwd and registry packages in e2etest job

This is admittedly "scope creep" for a job that was originally intended
only to run the end-to-end tests, but we have a separate e2etest job
specifically because some of these tests interact with the live OpenTofu
Registry and certain GitHub repositories and so it's nice to have these
external dependencies isolated into their own job so that outages of any
of these external services should only affect this one test job.

The TF_ACC=1-constrained tests in packages initwd and registry are set up
that way because they too interact with OpenTofu Registry and GitHub
repositories, so grouping these together retains the idea of limited
these external dependencies to only one job while giving us a little more
test coverage for our PR checks.

The motivation for doing this now is that both of these packages had
acceptance tests that had been broken by changes in the past and we didn't
notice because nothing was routinely running these tests:
- package registry had been failing ever since OpenTofu existed because
  one of its tests seems to have been depending on an undocumented registry
  protocol feature that OpenTofu Registry has never implemented
- package initwd got broken more recently by a change to use a dependency
  inversion style for the module installer's use of module registry client
  and package fetcher, but these particular tests were not passing in
  working clients for the module installer to use.

Both of those problems were already fixed in earlier commits, and so this
is just an attempt to avoid similar problems happening again in future.

(This doesn't address the more common case of acceptance tests that require
live credentials to access a service that doesn't support anonymous access.
Those will still need to run manually in development environments because
we cannot pass live credentials to a job that runs in response to
third-party pull requests.)

Signed-off-by: Martin Atkins <mart@degeneration.co.uk>

.github/workflows/checks.yml

@@ -125,7 +125,15 @@ jobs:
 
       - name: "End-to-end tests"
         run: |
-          TF_ACC=1 go test -v ./internal/command/e2etest
+          # This also includes some acceptance tests elsewhere that have
+          # similar dependencies on the OpenTofu Registry and on some
+          # OpenTofu-controlled GitHub repositories, just because this
+          # particular job is already expected to have that kind of external
+          # dependency. Note that this is appropriate only for tests that
+          # make _unauthenticated_ requests to external network services,
+          # because we mustn't put live credentials in a job that can be
+          # triggered by community pull requests.
+          TF_ACC=1 go test -v ./internal/command/e2etest ./internal/initwd ./internal/registry
 
   consistency-checks:
     name: "Code Consistency Checks"