Move registerCoreWithSerializer to its own file #2442

Job	Run time
Benchmarks	20m 9s
Lint	1m 4s
Flow	51s
Unit tests (ubuntu-latest, Node 18)	3m 7s
Unit tests (macos-latest, Node 18)	8m 9s
Integration tests (ubuntu-latest, Node 18)	6m 36s
Unit tests (windows-latest, Node 18)	8m 46s
Integration tests (macos-latest, Node 18)	18m 36s
Unit tests (ubuntu-latest, Node 20)	2m 57s
Integration tests (windows-latest, Node 18)	19m 42s
Unit tests (macos-latest, Node 20)	10m 22s
Integration tests (ubuntu-latest, Node 20)	6m 29s
Unit tests (windows-latest, Node 20)	6m 45s
Integration tests (macos-latest, Node 20)	15m 26s
Integration tests (windows-latest, Node 20)	11m 45s
Test report	4s
	2h 20m 48s

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