cgen: fix codegen for option on concatexpr (fix #22951) (#22964) #347

Job	Run time
tests-sanitize-address-gcc	2h 42m 27s
tests-sanitize-address-clang	2h 5m 52s
tests-sanitize-address-msvc	4m 16s
tests-sanitize-memory-clang	3h 28m 0s
tests-sanitize-undefined-gcc	1h 38m 45s
tests-sanitize-undefined-clang	1h 3m 21s
	11h 2m 41s

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