chore: remove unused types and constructors, use consistent naming #2727

Job	Run time
test / test-dart-vm (3.0.1)	4m 13s
test / test-dart-vm (stable)	4m 19s
native_test / test-dart-native (macos-latest)	5m 43s
native_test / test-dart-native (windows-latest)	8m 7s
dart2js_test / test-dart-2js (3.0.1, chrome)	14m 6s
dart2js_test / test-dart-2js (3.0.1, firefox)	14m 31s
dart2js_test / test-dart-2js (stable, chrome)	14m 47s
dart2js_test / test-dart-2js (stable, firefox)	14m 25s
ddc_test / test-dart-ddc (3.0.1, chrome)	11m 2s
ddc_test / test-dart-ddc (3.0.1, firefox)	10m 56s
ddc_test / test-dart-ddc (stable, chrome)	9m 53s
ddc_test / test-dart-ddc (stable, firefox)	10m 35s
	2h 2m 37s

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