pkg/testutils/lint: add a linter rule to block call to debug.Stack()

Some of the previous commits addressed the unnecessary redaction of
stack traces by replacing uses of debug.Stack() with debugutil.Stack().
The new function ensures proper handling of redaction.

This commit future-proofs the solution by adding a linter rule to block
future uses of debug.Stack(). The linter error will prompt users to use
debugutil.Stack() instead.

Part of: CRDB-15292
Epic: CRDB-37533
Release note: None

pkg/testutils/lint/lint_test.go

@@ -2882,4 +2882,35 @@ func TestLint(t *testing.T) {
 		}
 	})
 
+	t.Run("TestDebugStack", func(t *testing.T) {
+		t.Parallel()
+
+		excludeFiles := []string{
+			":!util/debugutil/debugutil.go",
+			":!server/debug/goroutineui/dump_test.go",
+		}
+
+		cmd, stderr, filter, err := dirCmd(pkgDir, "git", append([]string{
+			"grep", "-nE", `debug\.Stack\(`, "--", "*.go",
+		}, excludeFiles...)...)
+		if err != nil {
+			t.Fatal(err)
+		}
+
+		if err := cmd.Start(); err != nil {
+			t.Fatal(err)
+		}
+
+		if err := stream.ForEach(filter, func(s string) {
+			t.Errorf("\n%s <- forbidden; use 'debugutil.Stack()' instead", s)
+		}); err != nil {
+			t.Error(err)
+		}
+
+		if err := cmd.Wait(); err != nil {
+			if out := stderr.String(); len(out) > 0 {
+				t.Fatalf("err=%s, stderr=%s", err, out)
+			}
+		}
+	})
 }