refactor: fix `nullCoalesce.variable` errors #13122

Job	Run time
Setup PHP Version for Code Coverage	2s
Others (8.3) / Sanity Tests	2m 24s
Others (8.2) / Sanity Tests	3m 43s
Others (8.1) / Sanity Tests	2m 46s
Others (8.4) / Sanity Tests	2m 24s
SeparateProcess (8.2) / tests	3m 27s
SeparateProcess (8.3) / tests	3m 26s
SeparateProcess (8.1) / tests	3m 12s
CacheLive (8.4) / Cache Live Tests	2m 18s
CacheLive (8.1) / Cache Live Tests	2m 1s
CacheLive (8.2) / Cache Live Tests	2m 19s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 39s
DatabaseLive (8.1, MySQLi, 8.0) / tests	5m 49s
CacheLive (8.3) / Cache Live Tests	2m 1s
DatabaseLive (8.1, OCI8, 8.0) / tests	6m 9s
SeparateProcess (8.4) / tests	3m 7s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 25s
DatabaseLive (8.3, SQLite3, 8.0) / tests	2m 38s
DatabaseLive (8.4, OCI8, 8.0) / tests	6m 44s
DatabaseLive (8.3, OCI8, 8.0) / tests	6m 25s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 27s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 21s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 52s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 49s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	5m 22s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 9s
DatabaseLive (8.4, MySQLi, 8.0) / tests	4m 22s
DatabaseLive (8.1, MySQLi, 5.7) / tests	3m 43s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	5m 49s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 2s
DatabaseLive (8.2, OCI8, 8.0) / tests	6m 43s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 42s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 43s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 57s
Upload coverage results to Coveralls / coveralls	42s
	2h 8m 42s

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