t/helper: merge test-dump-split-index into test-tool

Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

t/helper/test-dump-split-index.c

@@ -1,3 +1,4 @@
+#include "test-tool.h"
 #include "cache.h"
 #include "split-index.h"
 #include "ewah/ewok.h"
@@ -7,7 +8,7 @@ static void show_bit(size_t pos, void *data)
 	printf(" %d", (int)pos);
 }
 
-int cmd_main(int ac, const char **av)
+int cmd__dump_split_index(int ac, const char **av)
 {
 	struct split_index *si;
 	int i;