Add regression test for ICE in mono item collection

Add a build-pass test that exercises -Clink-dead-code=true with
generic_const_exprs and min_generic_const_args, which previously
caused an ICE in mono item collection.

Author: jeanibarz

tests/ui/const-generics/generic_const_exprs/ice-issue-149035.rs

@@ -0,0 +1,21 @@
+// Regression test for <https://github.com/rust-lang/rust/issues/149035>.
+//
+// Previously, using `-Clink-dead-code=true` with `generic_const_exprs` and
+// `min_generic_const_args` caused an ICE in mono item collection. Fixed by #152129.
+
+//@ build-pass
+//@ compile-flags: -Clink-dead-code=true
+
+#![feature(min_generic_const_args, generic_const_exprs)]
+#![allow(incomplete_features)]
+
+const L: usize = 4;
+trait Print<const N: usize> {
+    fn print() -> usize {
+        N
+    }
+}
+struct Printer;
+impl Print<L> for Printer {}
+
+fn main() {}