Deprecate downlevelIteration #35220

Job	Run time
knip	30s
typecheck	43s
format	23s
browser-integration	1m 30s
coverage	11m 16s
self-check	1m 3s
smoke	58s
misc	28s
package-size	1m 30s
baselines	8m 44s
Test Node 16 on windows-latest	13m 12s
Test Node 24 on macos-latest	11m 34s
Test Node 16 on ubuntu-latest	11m 38s
Test Node 22 on windows-latest	12m 22s
Test Node 14 on ubuntu-latest	11m 55s
Test Node 22 on ubuntu-latest	10m 16s
Test Node 18 on ubuntu-latest	11m 48s
Test Node 24 on windows-latest	10m 0s
Test Node lts/* on ubuntu-latest with --no-bundle	11m 3s
lint	1m 0s
Test Node 18 on windows-latest	13m 14s
Test Node 20 on ubuntu-latest	10m 16s
Test Node 20 on windows-latest	12m 38s
Test Node 14 on windows-latest	14m 37s
Test Node 24 on ubuntu-latest	8m 28s
Test Node 16 on macos-latest	19m 6s
required	3s
	3h 30m 15s

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