gh-121973: Fix flaky test_pyrepl tests

This fixes the flakiness in:
* test_inspect_keeps_globals_from_inspected_file
* test_inspect_keeps_globals_from_inspected_module

The output already includes newlines. Adding newlines for every entry in
the output list introduces non-determinism because it added '\n' in
places where stdout is flushed or some buffer becomes full.

The regex also needed to be updated because pyrepl includes control
characters -- the visible output on each line doesn't immediately follow
a newline character.

Author: colesbury

Lib/test/test_pyrepl/test_pyrepl.py

@@ -989,7 +989,7 @@ def _run_repl_globals_test(self, expectations, *, as_file=False, as_module=False
         self.assertEqual(exit_code, 0)
         for var, expected in expectations.items():
             with self.subTest(var=var, expected=expected):
-                if m := re.search(rf"[\r\n]{var}=(.+?)[\r\n]", output):
+                if m := re.search(rf"[^{{]{var}=(.+?)[\r\n]", output):
                     self._assertMatchOK(var, expected, actual=m.group(1))
                 else:
                     self.fail(f"{var}= not found in output")
@@ -1126,4 +1126,4 @@ def run_repl(
         except subprocess.TimeoutExpired:
             process.kill()
             exit_code = process.wait()
-        return "\n".join(output), exit_code
+        return "".join(output), exit_code