Remove test that depends on rustc

There's already another test (run-pass/issue-2316-c) that tests for
the same bug. So there's no need to have this one, which depends on
librustc, in the test suite.

Closes #2368.

src/test/run-pass-fulldeps/issue-2316.rs

@@ -1,5 +0,0 @@
-use rustc;
-import rustc::middle::ty;
-fn main() {
-  let _t: ty::sty = rustc::middle::ty::ty_nil;
-}