Remove an unloaded file with syntax errors.

“If it’s not in use, kill it.”

I was just going and feeding everything through `rustc --pretty normal`, and I guess this file isn't in use:

```rust
src/librustc/middle/typeck/infer/test.rs:104:23: 104:27 error: found `self` in ident position
src/librustc/middle/typeck/infer/test.rs:104         fn search_mod(self: &Env,
                                                                   ^~~~
src/librustc/middle/typeck/infer/test.rs:117:19: 117:23 error: found `self` in ident position
src/librustc/middle/typeck/infer/test.rs:117         fn search(self: &Env,
                                                               ^~~~
src/librustc/middle/typeck/infer/test.rs:182:45: 182:46 error: expected one of `;`, `}` but found `:`
src/librustc/middle/typeck/infer/test.rs:182         let inputs = input_tys.map(|t| {mode: ast::expl(ast::by_copy),
                                                                                         ^
```

cc @nikomatsakis