Deprecate downlevelIteration #35175

Job	Run time
format	27s
browser-integration	1m 30s
coverage	10m 41s
typecheck	41s
misc	25s
self-check	55s
package-size	1m 32s
knip	36s
smoke	57s
baselines	9m 5s
lint	55s
Test Node 22 on windows-latest	11m 55s
Test Node 20 on ubuntu-latest	10m 35s
Test Node 22 on ubuntu-latest	9m 39s
Test Node 18 on windows-latest	13m 52s
Test Node 24 on macos-latest	9m 48s
Test Node 14 on windows-latest	14m 23s
Test Node 24 on windows-latest	9m 49s
Test Node 16 on windows-latest	13m 48s
Test Node 24 on ubuntu-latest	8m 7s
Test Node 18 on ubuntu-latest	11m 1s
Test Node lts/* on ubuntu-latest with --no-bundle	10m 35s
Test Node 16 on ubuntu-latest	11m 26s
Test Node 20 on windows-latest	12m 23s
Test Node 16 on macos-latest	13m 34s
Test Node 14 on ubuntu-latest	11m 32s
required	2s
	3h 20m 13s

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