fmt_test.go: remove redundant type conversion

Change-Id: I700d2b25c91938caa2b90dc3cb0cc2d94a3e0daf
GitHub-Last-Rev: 6d7d0646a4ca3a2a493459c914d397e3de27f9ea
GitHub-Pull-Request: golang/xerrors#4
Reviewed-on: https://go-review.googlesource.com/c/xerrors/+/428985
Reviewed-by: Heschi Kreinick <heschi@google.com>
Run-TryBot: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Heschi Kreinick <heschi@google.com>
Reviewed-by: Damien Neil <dneil@google.com>
1 file changed