ValueFlow: avoid unnecessary `ValuePtr` and `Value` copies #19267

Job	Run time
build_make (ubuntu:24.04)	2m 57s
build_cmake (ubuntu:25.10, true, true)	3m 18s
build_make (ubuntu:25.10)	3m 19s
build_cmake (ubuntu:24.04, true, true)	3m 11s
build_cmake (alpine:3.23, false, false)	4m 30s
build_make (alpine:3.23)	6m 18s
	23m 33s

Provide feedback