Corrected typos on reflection test #1886

Job	Run time
GROMACS (release-2022) / test_backends	17m 20s
LAMMPS (develop) / test_backends	19m 32s
NAMD (devel) / test_backends	6m 28s
VMD / test_backends	2m 20s
GROMACS (release-2023) / test_backends	18m 40s
GROMACS (main) / test_backends	2m 40s
	1h 7m 0s

Provide feedback