Remove workaround of #13793/#10872

LLVM assertion error has been fixed recently:
http://llvm.org/bugs/show_bug.cgi?id=18993

Fixes #13793

Author: klutzy

src/test/run-make/no-intermediate-extras/foo.rs

@@ -7,8 +7,3 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-
-// FIXME #13793
-#[test]
-fn test_dummy() {
-}

src/test/run-pass/issue-14393.rs

@@ -8,8 +8,6 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-// ignore-windows: FIXME #13793
-
 fn main() {
     match ("", 1u) {
         (_, 42u) => (),

src/test/run-pass/test-runner-hides-main.rs

@@ -9,7 +9,6 @@
 // except according to those terms.
 
 // compile-flags:--test
-// ignore-windows #10872
 // ignore-pretty: does not work well with `--test`
 
 // Building as a test runner means that a synthetic main will be run,