internal/codegen: fixes tests for new config

Adding
---
counter: tools/command:goimports
title: goimports command invocations
description: count the number of times goimports is invoked
type: partition
issue: https://github.com/golang/go/issues/75321
program: golang.org/x/tools/cmd/goimports
module: golang.org/x/tools

to config.txt caused the checking tests to fail on a local
machine.

This CL adds paddings for the new program, and avoids running
the test in the local copy of the repo. (The test is protected
by t.Short(). The change to config.txt is in a different CL.)

Change-Id: I8c94009c04aa72db334027498ae265c2c056961c
Reviewed-on: https://go-review.googlesource.com/c/telemetry/+/701717
Reviewed-by: Robert Findley <rfindley@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>

internal/configgen/main.go

diff --git a/internal/configgen/main.go b/internal/configgen/main.go
index afc9258..31c868a 100644
--- a/internal/configgen/main.go
+++ b/internal/configgen/main.go
@@ -70,6 +70,13 @@
 		patch:    1,
 		pre:      0,
 	},
+	"golang.org/x/tools/cmd/goimports": {
+		releases: 2,
+		maj:      0,
+		majmin:   1,
+		patch:    2,
+		pre:      0,
+	},
 }
 
 // regularPaddings maps from program name to padding used to reserve enough
@@ -112,6 +119,14 @@
 		patch:    2,
 		pre:      0,
 	},
+	"golang.org/x/tools/cmd/goimports": {
+		// same as gopls
+		releases: 6,
+		maj:      1,
+		majmin:   6,
+		patch:    3,
+		pre:      4,
+	},
 }
 
 func main() {
@@ -455,10 +470,18 @@
 // any escaping of upper-cased letters, as is required by the proxy prototol
 // (https://go.dev/ref/mod#goproxy-protocol).
 func listProxyVersions(modulePath string) ([]string, error) {
+	// Avoid problematic interactions with the local workspace by running in a
+	// temp directory.
+	listDir, err := os.MkdirTemp("", "")
+	if err != nil {
+		return nil, err
+	}
+	defer os.RemoveAll(listDir)
 	if vers, ok := versionsForTesting[modulePath]; ok {
 		return vers, nil
 	}
 	cmd := exec.Command("go", "list", "-m", "--versions", modulePath)
+	cmd.Dir = listDir
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
 	out, err := cmd.Output()