Citus regress tests using tdigest fails due to output diffs (seemingly normalization of the output does not happen anymore)

Install tdigest

Run
make check-base EXTRA_TESTS=tdigest_aggregate_support

QUERY PLAN
-------------------------------------------------------------------------------------------------------------------------------------------

```
-
Aggregate
- Output: xxxxxx
+ Output: tdigest(remote_scan.tdigest)
-> Custom Scan (Citus Adaptive)
- Output: xxxxxx
+ Output: remote_scan.tdigest
Task Count: 4
Tasks Shown: One of 4
-> Task
Query: SELECT public.tdigest(latency, 100) AS tdigest FROM tdigest_aggregate_support.latencies_20070000 latencies WHERE true
Node: host=localhost port=57637 dbname=regression
-> Aggregate
- Output: xxxxxx
+ Output: tdigest(latency, 100)
-> Seq Scan on tdigest_aggregate_support.latencies_20070000 latencies
- Output: xxxxxx
+ Output: a, b, latency
(13 rows)

......

```