Fix stale File status in tests (#15030)

## Summary

Fixes https://github.com/astral-sh/ruff/issues/15027

The `MemoryFileSystem::write_file` API automatically creates
non-existing ancestor directoryes
but we failed to update the status of the now created ancestor
directories in the `Files` data structure.


## Test Plan

Tested that the case in https://github.com/astral-sh/ruff/issues/15027
now passes regardless of whether the *Simple* case is commented out or
not

crates/red_knot_python_semantic/src/module_resolver/resolver.rs

@@ -73,6 +73,15 @@ enum SystemOrVendoredPathRef<'a> {
     Vendored(&'a VendoredPath),
 }
 
+impl std::fmt::Display for SystemOrVendoredPathRef<'_> {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            SystemOrVendoredPathRef::System(system) => system.fmt(f),
+            SystemOrVendoredPathRef::Vendored(vendored) => vendored.fmt(f),
+        }
+    }
+}
+
 /// Resolves the module for the file with the given id.
 ///
 /// Returns `None` if the file is not a module locatable via any of the known search paths.

crates/red_knot_python_semantic/src/types/infer.rs

@@ -124,7 +124,6 @@ pub(crate) fn infer_definition_types<'db>(
     let file = definition.file(db);
     let _span = tracing::trace_span!(
         "infer_definition_types",
-        definition = ?definition.as_id(),
         range = ?definition.kind(db).range(),
         file = %file.path(db)
     )

crates/ruff_db/src/system/test.rs

@@ -175,19 +175,26 @@ pub trait DbWithTestSystem: Db + Sized {
     ///
     /// # Panics
     /// If the system isn't using the memory file system.
-    fn write_file(
-        &mut self,
-        path: impl AsRef<SystemPath>,
-        content: impl ToString,
-    ) -> crate::system::Result<()> {
+    fn write_file(&mut self, path: impl AsRef<SystemPath>, content: impl ToString) -> Result<()> {
         let path = path.as_ref();
-        let result = self
-            .test_system()
-            .memory_file_system()
-            .write_file(path, content);
+
+        let memory_fs = self.test_system().memory_file_system();
+
+        let sync_ancestors = path
+            .parent()
+            .is_some_and(|parent| !memory_fs.exists(parent));
+        let result = memory_fs.write_file(path, content);
 
         if result.is_ok() {
             File::sync_path(self, path);
+
+            // Sync the ancestor paths if the path's parent
+            // directory didn't exist before.
+            if sync_ancestors {
+                for ancestor in path.ancestors() {
+                    File::sync_path(self, ancestor);
+                }
+            }
         }
 
         result