[committed] testsuite: Add missing header to test

[Jonathan Wakely via Gcc-patches]

This fixes a new FAIL caused by my r12-7699 change to libstdc++ headers.

Pushed to trunk as obvious.

-- >8 --

gcc/testsuite/ChangeLog:

        * g++.dg/torture/pr104601.C: Include <vector>.
---
 gcc/testsuite/g++.dg/torture/pr104601.C | 1 +
 1 file changed, 1 insertion(+)

diff --git a/gcc/testsuite/g++.dg/torture/pr104601.C 
b/gcc/testsuite/g++.dg/torture/pr104601.C
index bb56479c745..92ad73d47e9 100644
--- a/gcc/testsuite/g++.dg/torture/pr104601.C
+++ b/gcc/testsuite/g++.dg/torture/pr104601.C
@@ -4,6 +4,7 @@
 
 #include <algorithm>
 #include <optional>
+#include <vector>
 
 inline std::optional<int>
 foo (std::vector<int>::iterator b, std::vector<int>::iterator c,
-- 
2.34.1