Bring back zed.rs tests (#3907)

At present 3 tests still fail; 2 are related to keymap issues that (I
believe) @maxbrunsfeld is working on. The other one
(`test_open_paths_action`) I'll look into. edit: done
This PR also fixes workspace unregistration, as we've put the code to do
that behind `debug_assert`
(https://github.com/zed-industries/zed/pull/3907/files#diff-041673bbd1947a35d45945636c0055429dfc8b5985faf93f8a8a960c9ad31e28L649).
Release Notes:
- N/A

crates/gpui/src/view.rs

@@ -6,7 +6,7 @@ use crate::{
 };
 use anyhow::{Context, Result};
 use std::{
-    any::TypeId,
+    any::{type_name, TypeId},
     fmt,
     hash::{Hash, Hasher},
 };
@@ -104,6 +104,14 @@ impl<V> Clone for View<V> {
     }
 }
 
+impl<T> std::fmt::Debug for View<T> {
+    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+        f.debug_struct(&format!("View<{}>", type_name::<T>()))
+            .field("entity_id", &self.model.entity_id)
+            .finish_non_exhaustive()
+    }
+}
+
 impl<V> Hash for View<V> {
     fn hash<H: Hasher>(&self, state: &mut H) {
         self.model.hash(state);