expression: replace recursive Tree datatype with a non-recursive one
#2130
| Job | Run time |
|---|---|
| 3m 26s | |
| 35s | |
| 41s | |
| 1m 27s | |
| 14s | |
| 42s | |
| 56s | |
| 25m 16s | |
| 1m 1s | |
| 14m 51s | |
| 26m 41s | |
| 15m 35s | |
| 1m 10s | |
| 14m 26s | |
| 15m 30s | |
| 1m 7s | |
| 52s | |
| 59s | |
| 54s | |
| 53s | |
| 54s | |
| 1m 0s | |
| 59s | |
| 51s | |
| 49s | |
| 51s | |
| 49s | |
| 53s | |
| 50s | |
| 2h 15m 12s |