ci: Don't exclude ctest/

There are no longer any shell files in `ctest/`, so this FIXME can be
resolved.

Also move this to the end so missing shellcheck doesn't exit before the
sort checks.

(backport <#4454>)
[ note - this backport doesn't do much since `ctest/` was never
  excluded, but it does keep file structure in sync - Trevor ]
(cherry picked from commit 654bf4e)

Author: tgross35

ci/style.sh

@@ -63,13 +63,6 @@ rm "$tmpfile"
 # individual file.
 cargo fmt
 
-if shellcheck --version ; then
-    find . -name '*.sh' -print0 | xargs -0 shellcheck
-else
-    echo "shellcheck not found"
-    exit 1
-fi
-
 # Ensure that `sort` output is not locale-dependent
 export LC_ALL=C
 
@@ -91,3 +84,10 @@ for file in libc-test/semver/*.txt; do
         exit 1
     fi
 done
+
+if shellcheck --version ; then
+    find . -name '*.sh' -print0 | xargs -0 shellcheck
+else
+    echo "shellcheck not found"
+    exit 1
+fi