bpo-29240, bpo-32030: pymain_set_sys_argv() now copies argv

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• Rename pymain_set_argv() to pymain_set_sys_argv()
• pymain_set_sys_argv() now creates of copy of argv and modify the
  copy, rather than modifying pymain->argv
• Call pymain_set_sys_argv() earlier: before pymain_run_python(), but
  after pymain_get_importer().
• Add _PySys_SetArgvWithError() to handle errors

https://bugs.python.org/issue29240

[vstinner]

AppVeyor failed with:

ls failed
ok
======================================================================
ERROR: test_get_exe_bytes (distutils.tests.test_bdist_wininst.BuildWinInstTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "C:\projects\cpython\lib\distutils\tests\test_bdist_wininst.py", line 24, in test_get_exe_bytes
    exe_file = cmd.get_exe_bytes()
  File "C:\projects\cpython\lib\distutils\command\bdist_wininst.py", line 361, in get_exe_bytes
    f = open(filename, "rb")
FileNotFoundError: [Errno 2] No such file or directory: 'C:\\projects\\cpython\\lib\\distutils\\command\\wininst-14.12.exe'

I'm unable to reproduce the issue on my Windows :-(

[vstinner]

ERROR: test_get_exe_bytes (distutils.tests.test_bdist_wininst.BuildWinInstTestCase)

This error is unrelated to this change: see https://bugs.python.org/issue32302