remove unneeded #include (#7446)

diff --git a/iree/tools/iree-e2e-matmul-test.c b/iree/tools/iree-e2e-matmul-test.c
index a48fb8d..6c32737 100644
--- a/iree/tools/iree-e2e-matmul-test.c
+++ b/iree/tools/iree-e2e-matmul-test.c
@@ -8,7 +8,6 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <unistd.h>
 
 #include "iree/base/api.h"
 #include "iree/base/internal/file_path.h"