fix: report error for mulitple union type (#2872) #4756

Job	Run time
Check	4s
Runtimes	30s
Compiler (ubuntu, node current)	1m 55s
Compiler (ubuntu, node lts/*)	1m 57s
Coverage	4m 14s
Bootstrap (debug)	6m 6s
Compiler (macos, node current)	1m 14s
Features	22s
Bootstrap (release)	6m 34s
Compiler (macos, node lts/*)	1m 12s
Loader	20s
Compiler (windows, node current)	1m 55s
Compiler (windows, node lts/*)	2m 17s
	28m 40s

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