selftests/bpf: Convert comma to semicolon

Replace comma between expressions with semicolons.

Using a ',' in place of a ';' can have unintended side effects.
Although that is not the case here, it is seems best to use ';'
unless ',' is intended.

Found by inspection.
No functional change intended.
Compile tested only.

Signed-off-by: Chen Ni <nichen@iscas.ac.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Anton Protopopov <aspsk@isovalent.com>
Link: https://lore.kernel.org/bpf/20250310032045.651068-1-nichen@iscas.ac.cn


Signed-off-by: Alexei Starovoitov <ast@kernel.org>