perf tools: Add missing headers, mostly stdlib.h

Part of the erosion of util/util.h, that will lose its include stdlib.h,
we need to add it to places where it is needed but was getting it
indirectly.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lkml.kernel.org/n/tip-1imnqezw99ahc07fjeb51qby@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/llvm.c

@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdio.h>
+#include <stdlib.h>
 #include <bpf/libbpf.h>
 #include <util/llvm-utils.h>
 #include <util/cache.h>

tools/perf/tests/sample-parsing.c

@@ -1,6 +1,7 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdbool.h>
 #include <inttypes.h>
+#include <stdlib.h>
 #include <linux/bitops.h>
 #include <linux/kernel.h>
 #include <linux/types.h>

tools/perf/tests/vmlinux-kallsyms.c

@@ -3,6 +3,7 @@
 #include <linux/rbtree.h>
 #include <inttypes.h>
 #include <string.h>
+#include <stdlib.h>
 #include "map.h"
 #include "symbol.h"
 #include "util.h"