script: fixes shellquote

[lygstate]

This is for python 3.12

C:\src\VK-GL-CTS\external\..\scripts\build\common.py:70: SyntaxWarning: invalid escape sequence '\$'
  return '"%s"' % s.replace('\\', '\\\\').replace('"', '\"').replace('$', '\$').replace('`', '\`')
C:\src\VK-GL-CTS\external\..\scripts\build\common.py:70: SyntaxWarning: invalid escape sequence '\`'
  return '"%s"' % s.replace('\\', '\\\\').replace('"', '\"').replace('$', '\$').replace('`', '\`')

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