Test for use of break as an expression

The test was meant to verify that the typechecker correctly
allows a _|_ value (break, here) to be used in any context.
However, the compiler fails with an LLVM assertion failure.
I xfailed it, but wanted it to be on the record anyway.

Author: catamorphism

src/test/run-pass/break-value.rs

@@ -0,0 +1,13 @@
+//xfail-stage0
+//xfail-stage1
+//xfail-stage2
+//xfail-stage3
+fn int_id(int x) -> int {
+  ret x;
+}
+
+fn main() {
+  while(true) {
+      int_id(break);
+  }
+}