json: fix trailing space in base64 data

golang/go@20d745c made encoding/base64 pickier about trailing data
such as the extra space at the end of the json base64 data. As a
result, bench now panics with an "unexpected EOF" when starting (even
if you're not running the json benchmark, since this happens at init

Fix this by removing the trailing space.

Change-Id: I312ca0def3bb295c1f19a6ebdaf136ce27591da9
Reviewed-on: https://go-review.googlesource.com/18530
Reviewed-by: Dmitry Vyukov <dvyukov@google.com>
1 file changed