encoding/json: don't reset before returning buffer to pool

Reset is already performed when retrieving from pool

Change-Id: Ia810dd18d3e55a1565a5ad435a00d1e46724576c
GitHub-Last-Rev: d9df74a4aeb86e5d292c9fc33568a3c9a64a967d
GitHub-Pull-Request: golang/go#34195
Reviewed-on: https://go-review.googlesource.com/c/go/+/194338
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Daniel Martí <mvdan@mvdan.cc>

encode.go

@@ -164,7 +164,6 @@ func Marshal(v interface{}) ([]byte, error) {
 	}
 	buf := append([]byte(nil), e.Bytes()...)
 
-	e.Reset()
 	encodeStatePool.Put(e)
 
 	return buf, nil