added 'suggest-private-fields' cfail test

Author: Junseok Lee

src/test/compile-fail/suggest-private-fields.rs

@@ -0,0 +1,13 @@
+// aux-build:struct-field-privacy.rs
+
+extern crate "struct-field-privacy" as xc;
+
+use xc::B;
+
+fn main () {
+    let k = B {
+        aa: 20, //~ ERROR structure `struct-field-privacy::B` has no field named `aa`
+        //~^ HELP did you mean `a`?
+        bb: 20, //~ ERROR structure `struct-field-privacy::B` has no field named `bb`
+    };
+}