Defining `flatten` no longer requires special treatment (#882) #3498

Job	Run time
Setup Build Matrix (true, ion-rust, windows, macos, ubuntu, al2-x86, al2-arm, windows, macos, ubu...	1s
Build and Test (windows, default)	4m 15s
Build and Test (windows, all)	5m 23s
Build and Test (windows, experimental-ion-hash)	6m 33s
Build and Test (windows, experimental)	7m 10s
Build and Test (macos, default)	2m 27s
Build and Test (macos, all)	2m 19s
Build and Test (macos, experimental-ion-hash)	2m 11s
Build and Test (macos, experimental)	2m 27s
Build and Test (ubuntu, default)	2m 4s
Build and Test (ubuntu, all)	4m 36s
Build and Test (ubuntu, experimental-ion-hash)	2m 36s
Build and Test (ubuntu, experimental)	3m 9s
Build and Test (al2-x86, default)	1m 41s
Build and Test (al2-x86, all)	2m 7s
Build and Test (al2-x86, experimental-ion-hash)	2m 1s
Build and Test (al2-x86, experimental)	2m 5s
Build and Test (al2-arm, default)	1m 38s
Build and Test (al2-arm, all)	2m 4s
Build and Test (al2-arm, experimental-ion-hash)	1m 43s
Build and Test (al2-arm, experimental)	2m 8s
Build and Test Confirmation	1s
	1h 0m 39s

Provide feedback