perf debug: Remove needless include directives from debug.h

All we need there is a forward declaration for 'union perf_event', so
remove it from there and add missing header directives in places using
things from this indirect include.

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-7ftk0ztstqub1tirjj8o8xbl@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/thread-map.c

@@ -1,12 +1,19 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <stdlib.h>
+#include <string.h>
 #include <sys/types.h>
 #include <unistd.h>
 #include <sys/prctl.h>
 #include "tests.h"
 #include "thread_map.h"
 #include "debug.h"
+#include "event.h"
 #include <linux/zalloc.h>
+#include <perf/event.h>
+
+struct perf_sample;
+struct perf_tool;
+struct machine;
 
 #define NAME	(const char *) "perf"
 #define NAMEUL	(unsigned long) NAME