Move test file to run-fail, since it does an unwrap

Author: nikomatsakis

src/test/run-pass/issue-28934.rs renamed to src/test/run-fail/issue-28934.rs

@@ -11,6 +11,8 @@
 // Regression test: issue had to do with "givens" in region inference,
 // which were not being considered during the contraction phase.
 
+// error-pattern:explicit panic
+
 struct Parser<'i: 't, 't>(&'i u8, &'t u8);
 
 impl<'i, 't> Parser<'i, 't> {