Reenable some ignored test cases

* src/test/run-pass/issue-3559.rs was fixed in #4726
* src/test/compile-fail/borrowck-call-sendfn.rs was fixed in #2978
* update src/test/compile-fail/issue-5500-1.rs to work with current Rust
* removed src/test/compile-fail/issue-5500.rs because it is tested in
    src/test/run-fail/issue-5500.rs
* src/test/compile-fail/view-items-at-top.rs fixed
* #897 fixed
* compile-fail/issue-6762.rs issue was closed as dup of #6801
* deleted compile-fail/issue-2074.rs because it became irelevant and is
  irrelevant #2074, a test covering this was added in
  4f92f452bd701fb39156d66d4756cc48cc396a8a