Fix #14742 fuzzing crash (stack-overflow) in CheckNullPointer::nullPo… #20320

Job	Run time
build_cmake (ubuntu:24.04, true, true)	2m 57s
build_make (alpine:3.23)	5m 16s
build_make (ubuntu:24.04)	3m 16s
build_make (ubuntu:25.10)	3m 35s
build_cmake (alpine:3.23, false, false)	4m 37s
build_cmake (ubuntu:25.10, true, true)	3m 2s
	22m 43s

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