testing: remove redundant type conversion
testing: remove redundant type conversion

Change-Id: Ib6415bb09af02e9ebc0099f50bf0fd7b572f2516
GitHub-Last-Rev: ebaa849d66efa45bd8ca50a8306652d823a41678
GitHub-Pull-Request: golang/go#49244
Reviewed-on: https://go-review.googlesource.com/c/go/+/360214
Trust: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
Run-TryBot: Tobias Klauser <0a68dd4915066ec5d3f81f75a828fee53dcc8822@gmail.com>
TryBot-Result: Go Bot <66cb808b70d30c07676d5e946fee83fd561249e5@golang.org>
Reviewed-by: Emmanuel Odeke <bd234ba4276433f0e5fc7a8fa2d18274fa711567@orijtech.com>

golang/go,cloudflare/go,nawawi/go,CAFxX/go,cloudflare/go,nawawi/go,cloudflare/go,nawawi/go,CAFxX/go,nawawi/go,CAFxX/go,nawawi/go,golang/go,golang/go,golang/go,cloudflare/go,cloudflare/go,CAFxX/go,CAFxX/go,nawawi/go,golang/go,golang/go,nawawi/go,golang/go,cloudflare/go,cloudflare/go,golang/go,CAFxX/go,nawawi/go,cloudflare/go,CAFxX/go,CAFxX/go