Fully qualify values exported to host linking

Previously we were only handing off exposed values based on their
inner-module ID, but actually the fully-resolved ID is needed, because
it's reasonable that two identical names from different modules are
exposed to the host.

Closes #3483

crates/cli/src/build.rs

@@ -114,14 +114,26 @@ pub fn build_file<'a>(
         .exposed_to_host
         .values
         .keys()
-        .map(|x| x.as_str(&loaded.interns).to_string())
+        .map(|x| {
+            format!(
+                "{}.{}",
+                x.module_string(&loaded.interns),
+                x.as_str(&loaded.interns)
+            )
+        })
         .collect();
 
     let exposed_closure_types = loaded
         .exposed_to_host
         .closure_types
         .iter()
-        .map(|x| x.as_str(&loaded.interns).to_string())
+        .map(|x| {
+            format!(
+                "{}.{}",
+                x.module_string(&loaded.interns),
+                x.as_str(&loaded.interns)
+            )
+        })
         .collect();
 
     let preprocessed_host_path = if emit_wasm {