Add jemalloc to test -sys style dependencies

tests/src/main.rs

@@ -1,3 +1,10 @@
+#[cfg(not(target_env = "msvc"))]
+use tikv_jemallocator::Jemalloc;
+
+#[cfg(not(target_env = "msvc"))]
+#[global_allocator]
+static GLOBAL: Jemalloc = Jemalloc;
+
 fn main() {
     println!("Hello, world!");
 }