refactor(transformer/arrow-functions): add TODO comments #25948

Job	Run time
Build Linter Benchmark	2m 38s
Benchmark (lexer)	1m 32s
Benchmark (parser)	1m 28s
Benchmark (transformer)	2m 3s
Benchmark (isolated_declarations)	1m 49s
Benchmark (semantic)	1m 28s
Benchmark (minifier)	2m 33s
Benchmark (codegen)	2m 13s
Benchmark linter (0)	3m 1s
Benchmark linter (1)	1m 55s
Upload benchmarks	23s
	21m 3s

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