test: Add a test for #1696

Author: brson

src/test/run-pass/issue-1696.rs

@@ -0,0 +1,8 @@
+use std;
+import std::map;
+
+fn main() {
+    let m = map::new_bytes_hash();
+    m.insert(str::bytes("foo"), str::bytes("bar"));
+    log(error, m);
+}