cmds: static tmp_dirname used stack after return

[paranlee]

In cmds/live.c, There was stack use after return code.
tmp_dirname static char pointer would be not pointed stack allocation after command_live() call ended.
We can use tmp_dirname heap or fix sized array.

static char *tmp_dirname; // <<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
static void cleanup_tempdir(void)
{
	if (!tmp_dirname)
		return;

	remove_directory(tmp_dirname);
	tmp_dirname = NULL;
}

int command_live(int argc, char *argv[], struct uftrace_opts *opts)
{
#define LIVE_NAME "uftrace-live-XXXXXX"
	char template[32] = "/tmp/" LIVE_NAME; // <<<<<<<<<<<<<<<<<<<
	int fd;
	struct sigaction sa = {
		.sa_flags = SA_RESETHAND,
	};
	int ret;

	if (!opts->record) {
		tmp_dirname = template; // <<<<<<<<<<<<<<<<<<<<<<<<<<<

[yskelg]

This detected when agent tracing on/off with make ASAN=1.
I've checked from valkey

# valkey server on
$ uftrace record --agent --trace=off ./valkey-server

# valkey-server trace on/off
$ uftrace --pid `pidof valkey-server`  --trace=on
$ uftrace --pid `pidof valkey-server`  --trace=off

This would be stack-use-after- return on x86_64 Cent OS 7.

84462==ERROR： AddressSanitizer: stack-use-after- return on address 0x7f7eaf900020 at pc 0x7f7eb3d0a411 bp 0x7ffcc4a464c0 sp 0x7ffcc4a45c80
READ of size 25 at 0x7f7eaf900020 thread To
#0 0x7f7eb3d0a410 in __interceptor_opendir gcc-releases-gcc-13.2.0/libsanitizer/sanitizer/common/sanitizer_common_interceptors.inc: 3429
#1 0x586693 in remove_directory uftrace/utils/utils.c: 169
#2 0x447f42 in cleanup_tempdir uftrace/cds/live.c: 22
#3 0x7f7eb21bace8 in __run_exit_handlers (/lib64/libc.so.6+0x39ce8) (BuildId: fc4fa58e47a5acc137eadb7689bce4357c557a96)
#4 0x7f7eb21bad36 in exit (/lib64/libc.so.6+0x39d36) (BuildId: fc4fa5847a5acc137eadb7689bce4357c557a96)
#5 0x7f7eb21a355b in libc start main (/lib64/libc.so.6+0x2255b) (BuildId: fc4fa58e47a5acc137eadb7689bce4357c557a96)