perf record: Fix possible incorrect free in record__switch_output()

perf record: Fix possible incorrect free in record__switch_output()

perf_data__switch() may not assign a legal value to 'new_filename'.
In this case, 'new_filename' uses the on-stack value, which may cause a
incorrect free and unexpected result.

Fixes: 03724b2e9c45 ("perf record: Allow to limit number of reported perf.data files")
Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240119040304.3708522-2-yangjihong1@huawei.com
Signed-off-by: Namhyung Kim <namhyung@kernel.org>