Skip test in tests/tool-caml-tex/redirections.ml if native compiler is disabled
Skip test in tests/tool-caml-tex/redirections.ml if native compiler is disabled

This is a follow-up to GPR #1863. Without this commit, the
test in tests/tool-caml-tex/redirections.ml fails when the native
compiler is disabled.

This commit thus makes sure the native compiler is enabled before proceeding.

gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml