test: remove unwrap.rs

The file is testing `unwrap_used`, but that's already covered by the
`unwrap_expect_used.rs` test file

tests/ui/unwrap.rs

@@ -1,22 +0,0 @@
-#![warn(clippy::unwrap_used)]
-#![allow(clippy::unnecessary_literal_unwrap)]
-
-fn unwrap_option() {
-    let opt = Some(0);
-    let _ = opt.unwrap();
-    //~^ unwrap_used
-}
-
-fn unwrap_result() {
-    let res: Result<u8, u8> = Ok(0);
-    let _ = res.unwrap();
-    //~^ unwrap_used
-
-    let _ = res.unwrap_err();
-    //~^ unwrap_used
-}
-
-fn main() {
-    unwrap_option();
-    unwrap_result();
-}

tests/ui/unwrap.stderr

@@ -1,31 +0,0 @@
-error: used `unwrap()` on an `Option` value
-  --> tests/ui/unwrap.rs:6:13
-   |
-LL |     let _ = opt.unwrap();
-   |             ^^^^^^^^^^^^
-   |
-   = note: if this value is `None`, it will panic
-   = help: consider using `expect()` to provide a better panic message
-   = note: `-D clippy::unwrap-used` implied by `-D warnings`
-   = help: to override `-D warnings` add `#[allow(clippy::unwrap_used)]`
-
-error: used `unwrap()` on a `Result` value
-  --> tests/ui/unwrap.rs:12:13
-   |
-LL |     let _ = res.unwrap();
-   |             ^^^^^^^^^^^^
-   |
-   = note: if this value is an `Err`, it will panic
-   = help: consider using `expect()` to provide a better panic message
-
-error: used `unwrap_err()` on a `Result` value
-  --> tests/ui/unwrap.rs:15:13
-   |
-LL |     let _ = res.unwrap_err();
-   |             ^^^^^^^^^^^^^^^^
-   |
-   = note: if this value is an `Ok`, it will panic
-   = help: consider using `expect_err()` to provide a better panic message
-
-error: aborting due to 3 previous errors
-