added test for checking that ICEs are not hidden

src/test/incremental/delayed_span_bug.rs

@@ -0,0 +1,8 @@
+// revisions: cfail1 cfail2
+// should-ice
+// error-pattern: compilation successful
+
+#![feature(rustc_attrs)]
+
+#[rustc_error(delay_span_bug_from_inside_query)]
+fn main() {}