test: unify assertSnapshot common patterns #2957

Job	Run time
Build slim tarball	1m 27s
x86_64-darwin: with shared libraries	56m 30s
x86_64-linux: with shared libraries	2h 3m 10s
aarch64-linux: with shared libraries	1h 25m 58s
aarch64-darwin: with shared libraries	3h 27m 50s
	7h 54m 55s

Provide feedback