Fix issue with dry run

Author: Kobzol

src/bootstrap/src/core/build_steps/test.rs

@@ -1809,12 +1809,17 @@ NOTE: if you're sure you want to do this, please open an issue as to why. In the
             .stdout_if_ok();
         if let Some(ref vers) = lldb_version {
             cmd.arg("--lldb-version").arg(vers);
-            let lldb_python_dir = builder
-                .run(BootstrapCommand::new(&lldb_exe).allow_failure().capture_stdout().arg("-P"))
-                .stdout_if_ok()
-                .map(|p| p.lines().next().expect("lldb Python dir not found").to_string());
-            if let Some(ref dir) = lldb_python_dir {
-                cmd.arg("--lldb-python-dir").arg(dir);
+
+            if !builder.config.dry_run() {
+                let lldb_python_dir = builder
+                    .run(
+                        BootstrapCommand::new(&lldb_exe).allow_failure().capture_stdout().arg("-P"),
+                    )
+                    .stdout_if_ok()
+                    .map(|p| p.lines().next().expect("lldb Python dir not found").to_string());
+                if let Some(ref dir) = lldb_python_dir {
+                    cmd.arg("--lldb-python-dir").arg(dir);
+                }
             }
         }