Move /src/test to /tests

tests/rustdoc-ui/const-evalutation-ice.rs

@@ -0,0 +1,11 @@
+// Just check we don't get an ICE for `N`.
+
+use std::cell::Cell;
+use std::mem;
+
+pub struct S {
+    s: Cell<usize>
+}
+
+pub const N: usize = 0 - (mem::size_of::<S>() != 400) as usize;
+//~^ ERROR evaluation of constant value failed