Add a run-pass-valgrind test for vecdeque issue

src/test/run-pass-valgrind/issue-44800.rs

@@ -0,0 +1,25 @@
+// Copyright 2015 The Rust Project Developers. See the COPYRIGHT
+// file at the top-level directory of this distribution and at
+// http://rust-lang.org/COPYRIGHT.
+//
+// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
+// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
+// option. This file may not be copied, modified, or distributed
+// except according to those terms.
+
+#![feature(global_allocator, alloc_system, allocator_api)]
+extern crate alloc_system;
+
+use std::collections::VecDeque;
+use alloc_system::System;
+
+#[global_allocator]
+static ALLOCATOR: System = System;
+
+fn main() {
+    let mut deque = VecDeque::with_capacity(32);
+    deque.push_front(0);
+    deque.reserve(31);
+    deque.push_back(0);
+}