refactor: fix `nullCoalesce.variable` errors #13121

Job	Run time
Setup PHP Version for Code Coverage	4s
Others (8.1) / Sanity Tests	2m 27s
Others (8.2) / Sanity Tests	3m 57s
Others (8.3) / Sanity Tests	2m 24s
Others (8.4) / Sanity Tests	2m 42s
SeparateProcess (8.3) / tests	3m 24s
SeparateProcess (8.1) / tests	3m 33s
SeparateProcess (8.4) / tests	3m 2s
SeparateProcess (8.2) / tests	3m 33s
DatabaseLive (8.2, OCI8, 8.0) / tests	7m 5s
DatabaseLive (8.1, OCI8, 8.0) / tests	6m 1s
DatabaseLive (8.4, Postgre, 8.0) / tests	2m 53s
DatabaseLive (8.4, MySQLi, 8.0) / tests	5m 10s
DatabaseLive (8.4, SQLite3, 8.0) / tests	2m 44s
DatabaseLive (8.1, MySQLi, 5.7) / tests	2m 54s
DatabaseLive (8.2, MySQLi, 8.0) / tests	5m 43s
DatabaseLive (8.2, Postgre, 8.0) / tests	3m 3s
DatabaseLive (8.2, SQLite3, 8.0) / tests	3m 16s
DatabaseLive (8.3, SQLSRV, 8.0) / tests	5m 19s
DatabaseLive (8.1, Postgre, 8.0) / tests	2m 34s
DatabaseLive (8.3, MySQLi, 8.0) / tests	4m 55s
DatabaseLive (8.1, SQLSRV, 8.0) / tests	5m 33s
DatabaseLive (8.3, OCI8, 8.0) / tests	6m 36s
DatabaseLive (8.1, SQLite3, 8.0) / tests	2m 32s
DatabaseLive (8.3, Postgre, 8.0) / tests	2m 30s
DatabaseLive (8.1, MySQLi, 8.0) / tests	4m 34s
DatabaseLive (8.3, SQLite3, 8.0) / tests	3m 3s
CacheLive (8.3) / Cache Live Tests	2m 1s
DatabaseLive (8.4, SQLSRV, 8.0) / tests	5m 2s
CacheLive (8.2) / Cache Live Tests	2m 10s
CacheLive (8.1) / Cache Live Tests	2m 8s
DatabaseLive (8.2, SQLSRV, 8.0) / tests	5m 41s
DatabaseLive (8.4, OCI8, 8.0) / tests	5m 58s
CacheLive (8.4) / Cache Live Tests	2m 10s
Upload coverage results to Coveralls / coveralls	33s
	2h 7m 14s

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