Occasional test failures due to timeout on registry request

[kmoe]

The fix for this may well be in Core or the registry, but filing here for now.

Tests runs occasionally fail with a Failed to query available provider packages error like the following:

=== RUN   TestStateMv/basic_with_state-0.14.4
    util_test.go:111: [INFO] running Terraform command: /tmp/tfinstall187681955/v-0.14.4/terraform init -no-color -force-copy -input=false -lock-timeout=0s -backend=true -get=true -upgrade=false -lock=true -get-plugins=true -verify-plugins=true
    state_mv_test.go:23: error running Init in test directory: exit status 1
        
        Error: Failed to query available provider packages
        
        Could not retrieve the list of available versions for provider hashicorp/null:
        could not connect to registry.terraform.io: Failed to request discovery
        document: Get "https://registry.terraform.io/.well-known/terraform.json":
        net/http: request canceled while waiting for connection (Client.Timeout
        exceeded while awaiting headers)
        
--- FAIL: TestStateMv (13.12s)
    --- SKIP: TestStateMv/basic_with_state-0.11.14 (0.23s)
    --- SKIP: TestStateMv/basic_with_state-0.12.30 (0.47s)
    --- PASS: TestStateMv/basic_with_state-0.13.6 (1.12s)
    --- FAIL: TestStateMv/basic_with_state-0.14.4 (11.31s)

Example failing test run: https://app.circleci.com/pipelines/github/hashicorp/terraform-exec/661/workflows/bdc5a99c-63da-4f12-ad66-52df573f600c/jobs/9510

The tests pass when rerun.

More examples needed, but suspect this can happen during any test that runs terraform init.