refactor: fix `nullCoalesce.variable` errors #13132

Job	Run time
Setup PHP Version for Code Coverage	4s
Others (8.1) / Sanity Tests	3m 2s
Others (8.3) / Sanity Tests	2m 19s
Others (8.2) / Sanity Tests	3m 38s
Others (8.4) / Sanity Tests	2m 37s
SeparateProcess (8.3) / tests	3m 49s
SeparateProcess (8.2) / tests	3m 18s
SeparateProcess (8.1) / tests	3m 12s
SeparateProcess (8.4) / tests	3m 11s
CacheLive (8.3) / Cache Live Tests	1m 56s
CacheLive (8.2) / Cache Live Tests	2m 4s
CacheLive (8.1) / Cache Live Tests	2m 1s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 18s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 42s
CacheLive (8.4) / Cache Live Tests	2m 40s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	4m 50s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 15s
DatabaseLive (8.1, OCI8, 8.0) / tests	6m 15s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 29s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	4m 42s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 29s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 34s
DatabaseLive (8.3, OCI8, 8.0) / tests	6m 27s
DatabaseLive (8.4, OCI8, 8.0) / tests	6m 23s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 32s
DatabaseLive (8.1, MySQLi, 8.0) / tests	5m 55s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 35s
DatabaseLive (8.2, OCI8, 8.0) / tests	7m 1s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	5m 10s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 25s
DatabaseLive (8.1, MySQLi, 5.7) / tests	3m 18s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 48s
DatabaseLive (8.4, MySQLi, 8.0) / tests	5m 0s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 30s
Upload coverage results to Coveralls / coveralls	33s
	2h 7m 2s

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