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.
* Add msvcrt.GetErrorMode().
* SuppressCrashReport now uses GetErrorMode() and SetErrorMode() of
the msvcrt module, rather than using ctypes.
* Remove also an unused variable (deadline) in wait_process().
my_fgets() now calls _PyOS_InterruptOccurred(tstate) to check for
pending signals, rather calling PyOS_InterruptOccurred().
my_fgets() is called with the GIL released, whereas
PyOS_InterruptOccurred() must be called with the GIL held.
test_repl: use text=True and avoid SuppressCrashReport in
test_multiline_string_parsing().
Fix my_fgets() on Windows: fgets(fp) does crash if fileno(fp) is closed.