bpo-40826: Fix test_repl.test_close_stdin() on Windows (GH-20779) (GH-20785)

bpo-40826: Fix test_repl.test_close_stdin() on Windows (GH-20779) (GH-20785)

test_repl.test_close_stdin() now calls
support.suppress_msvcrt_asserts() to fix the test on Windows.

* Move suppress_msvcrt_asserts() from test.libregrtest.setup to
  test.support. Make its verbose parameter optional: verbose=False by
  default.
* SuppressCrashReport now uses SetErrorMode() of the msvcrt module,
  rather than using ctypes.
* Remove also an unused variable (deadline) in wait_process().

(cherry picked from commit f6e58aefde2e57e4cb11ea7743955da53a3f1e80)