Move /src/test to /tests

tests/ui/rfc-2632-const-trait-impl/const-impl-requires-const-trait.rs

@@ -0,0 +1,9 @@
+#![feature(const_trait_impl)]
+
+pub trait A {}
+//~^ HELP: mark `A` as const
+
+impl const A for () {}
+//~^ ERROR: const `impl` for trait `A` which is not marked with `#[const_trait]`
+
+fn main() {}