Deprecate downlevelIteration #35244

Job	Run time
browser-integration	1m 36s
baselines	9m 3s
typecheck	44s
misc	26s
coverage	10m 17s
package-size	1m 31s
smoke	53s
format	26s
knip	35s
lint	1m 0s
Test Node 20 on ubuntu-latest	10m 26s
Test Node 18 on ubuntu-latest	10m 48s
Test Node 24 on windows-latest	10m 21s
Test Node 24 on ubuntu-latest	8m 36s
Test Node 20 on windows-latest	12m 29s
Test Node 22 on ubuntu-latest	10m 25s
self-check	54s
Test Node 14 on ubuntu-latest	12m 4s
Test Node 22 on windows-latest	12m 59s
Test Node 18 on windows-latest	13m 32s
Test Node 14 on windows-latest	14m 10s
Test Node 24 on macos-latest	14m 0s
Test Node 16 on ubuntu-latest	11m 15s
Test Node lts/* on ubuntu-latest with --no-bundle	10m 43s
Test Node 16 on windows-latest	14m 18s
Test Node 16 on macos-latest	16m 8s
required	3s
	3h 29m 42s

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