refer to a different module in UI test

Author: joboet

tests/ui/stability-attribute/stability-in-private-module.rs

@@ -1,4 +1,4 @@
 fn main() {
-    let _ = std::thread::thread_info::current_thread();
-    //~^ERROR module `thread_info` is private
+    let _ = std::sys::os::errno();
+    //~^ERROR module `sys` is private
 }

tests/ui/stability-attribute/stability-in-private-module.stderr

@@ -1,13 +1,13 @@
-error[E0603]: module `thread_info` is private
-  --> $DIR/stability-in-private-module.rs:2:26
+error[E0603]: module `sys` is private
+  --> $DIR/stability-in-private-module.rs:2:18
    |
-LL |     let _ = std::thread::thread_info::current_thread();
-   |                          ^^^^^^^^^^^  -------------- function `current_thread` is not publicly re-exported
-   |                          |
-   |                          private module
+LL |     let _ = std::sys::os::errno();
+   |                  ^^^      ----- function `errno` is not publicly re-exported
+   |                  |
+   |                  private module
    |
-note: the module `thread_info` is defined here
-  --> $SRC_DIR/std/src/thread/mod.rs:LL:COL
+note: the module `sys` is defined here
+  --> $SRC_DIR/std/src/lib.rs:LL:COL
 
 error: aborting due to 1 previous error