Fix broken Values.Merge benchmark
Fix broken Values.Merge benchmark

Merge had the side effect of modifying the original values so
the results are wrong because they always hit the fast path
after the first run.

nooproblem/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,linearb/influxdb,mark-rushakoff/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,nooproblem/influxdb,benbjohnson/influxdb,li-ang/influxdb,archsaber/influxdb,linearb/influxdb,influxdb/influxdb,vladlopes/influxdb,nooproblem/influxdb,influxdb/influxdb,runner-mei/influxdb,influxdata/influxdb,runner-mei/influxdb,nooproblem/influxdb,influxdb/influxdb,mark-rushakoff/influxdb,benbjohnson/influxdb,linearb/influxdb,vladlopes/influxdb,runner-mei/influxdb,benbjohnson/influxdb,chenziliang/influxdb,chenziliang/influxdb,mark-rushakoff/influxdb,chenziliang/influxdb,vladlopes/influxdb,influxdb/influxdb,chenziliang/influxdb,benbjohnson/influxdb,archsaber/influxdb,mark-rushakoff/influxdb,influxdata/influxdb,archsaber/influxdb,influxdb/influxdb,li-ang/influxdb,archsaber/influxdb,linearb/influxdb,runner-mei/influxdb,linearb/influxdb,vladlopes/influxdb