fixup! fix exprt::opX accesses in linker_script_merge #11110

Job	Run time
check-ubuntu-24_04-make-clang	26m 23s
check-ubuntu-24_04-make-clang-smt-z3	8m 1s
check-string-table	1m 46s
check-ubuntu-24_04-cmake-gcc-14	15m 56s
check-macos-13-make-clang	27m 10s
check-vs-2019-cmake-build-and-test	1s
check-docker-image	20m 33s
windows-msi-package	1s
check-ubuntu-22_04-cmake-gcc	29m 2s
check-ubuntu-22_04-cmake-gcc-32bit	15m 10s
check-vs-2022-make-build-and-test	20m 40s
check-macos-14-cmake-clang	1h 34m 34s
check-ubuntu-24_04-cmake-gcc-KNOWNBUG	3m 19s
check-ubuntu-22_04-make-clang	17m 25s
check-ubuntu-24_04-make-gcc	33m 14s
include-what-you-use	16m 24s
check-ubuntu-24_04-cmake-gcc-THOROUGH	23m 27s
check-ubuntu-24_04-cmake-gcc	18m 18s
	6h 11m 24s

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