[ty] Remove vestigial pyvenv.cfg creation in mdtest (#18006)

Following #17991, removes some of
https://github.com/astral-sh/ruff/pull/17222 which is no longer strictly
necessary. I don't actually think it's that ugly to have around? no
strong feelings on retaining it or not.

crates/ty_test/src/lib.rs

@@ -170,7 +170,6 @@ fn run_test(
 
     let mut typeshed_files = vec![];
     let mut has_custom_versions_file = false;
-    let mut has_custom_pyvenv_cfg_file = false;
 
     let test_files: Vec<_> = test
         .files()
@@ -196,9 +195,8 @@ fn run_test(
                 }
             } else if let Some(python_path) = python_path {
                 if let Ok(relative_path) = full_path.strip_prefix(python_path) {
-                    if relative_path.as_str() == "pyvenv.cfg" {
-                        has_custom_pyvenv_cfg_file = true;
-                    } else {
+                    // Construct the path to the site-packages directory
+                    if relative_path.as_str() != "pyvenv.cfg" {
                         let mut new_path = SystemPathBuf::new();
                         for component in full_path.components() {
                             let component = component.as_str();
@@ -256,16 +254,6 @@ fn run_test(
         }
     }
 
-    if let Some(python_path) = python_path {
-        if !has_custom_pyvenv_cfg_file {
-            let pyvenv_cfg_file = python_path.join("pyvenv.cfg");
-            let home_directory = SystemPathBuf::from(format!("/Python{python_version}"));
-            db.create_directory_all(&home_directory).unwrap();
-            db.write_file(&pyvenv_cfg_file, format!("home = {home_directory}"))
-                .unwrap();
-        }
-    }
-
     let configuration = test.configuration();
 
     let settings = ProgramSettings {