perf tests record_offcpu.sh: Fix redirection of stderr to stdin

It's not 2&>1, the correct is 2>&1

Fixes: ade1d0307b ("perf offcpu: Update offcpu test for child process")
Signed-off-by: Patrice Duroux <patrice.duroux@gmail.com>
Acked-by: Ian Rogers <irogers@google.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20230303193058.21274-1-patrice.duroux@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/shell/record_offcpu.sh

@@ -65,7 +65,7 @@ test_offcpu_child() {
 
   # perf bench sched messaging creates 400 processes
   if ! perf record --off-cpu -e dummy -o ${perfdata} -- \
-    perf bench sched messaging -g 10 > /dev/null 2&>1
+    perf bench sched messaging -g 10 > /dev/null 2>&1
   then
     echo "Child task off-cpu test [Failed record]"
     err=1