Fix #14796: FP assertWithSideEffect for member functions without defi… #20455

Job	Run time
build_make (ubuntu:24.04)	3m 0s
build_cmake (ubuntu:25.10, true, true)	3m 12s
build_make (alpine:3.23)	5m 54s
build_cmake (ubuntu:24.04, true, true)	2m 59s
build_cmake (alpine:3.23, false, false)	2m 56s
build_make (ubuntu:25.10)	5m 2s
	23m 3s

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