perf tests: Add missing event.h include

It uses things like perf_event__name() but were not including event.h,
where its prototype lives, fix it.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/mmap-basic.c

@@ -5,6 +5,7 @@
 #include <perf/cpumap.h>
 
 #include "debug.h"
+#include "event.h"
 #include "evlist.h"
 #include "evsel.h"
 #include "thread_map.h"

tools/perf/tests/perf-record.c

@@ -5,6 +5,7 @@
 
 #include <sched.h>
 #include <perf/mmap.h>
+#include "event.h"
 #include "evlist.h"
 #include "evsel.h"
 #include "debug.h"