selftests/bpf: Clear out Python syntax warnings

selftests/bpf: Clear out Python syntax warnings

Invalid escape sequences are used, and produced syntax warnings:

  $ test_bpftool_synctypes.py
  test_bpftool_synctypes.py:69: SyntaxWarning: invalid escape sequence '\['
    self.start_marker = re.compile(f'(static )?const bool {self.array_name}\[.*\] = {{\n')
  test_bpftool_synctypes.py:83: SyntaxWarning: invalid escape sequence '\['
    pattern = re.compile('\[(BPF_\w*)\]\s*= (true|false),?$')
  test_bpftool_synctypes.py:181: SyntaxWarning: invalid escape sequence '\s'
    pattern = re.compile('^\s*(BPF_\w+),?(\s+/\*.*\*/)?$')
  test_bpftool_synctypes.py:229: SyntaxWarning: invalid escape sequence '\*'
    start_marker = re.compile(f'\*{block_name}\* := {{')
  test_bpftool_synctypes.py:229: SyntaxWarning: invalid escape sequence '\*'
    start_marker = re.compile(f'\*{block_name}\* := {{')
  test_bpftool_synctypes.py:230: SyntaxWarning: invalid escape sequence '\*'
    pattern = re.compile('\*\*([\w/-]+)\*\*')
  test_bpftool_synctypes.py:248: SyntaxWarning: invalid escape sequence '\s'
    start_marker = re.compile(f'"\s*{block_name} := {{')
  test_bpftool_synctypes.py:249: SyntaxWarning: invalid escape sequence '\w'
    pattern = re.compile('([\w/]+) [|}]')
  test_bpftool_synctypes.py:267: SyntaxWarning: invalid escape sequence '\s'
    start_marker = re.compile(f'"\s*{macro}\s*" [|}}]')
  test_bpftool_synctypes.py:267: SyntaxWarning: invalid escape sequence '\s'
    start_marker = re.compile(f'"\s*{macro}\s*" [|}}]')
  test_bpftool_synctypes.py:268: SyntaxWarning: invalid escape sequence '\w'
    pattern = re.compile('([\w-]+) ?(?:\||}[ }\]])')
  test_bpftool_synctypes.py:287: SyntaxWarning: invalid escape sequence '\w'
    pattern = re.compile('(?:.*=\')?([\w/]+)')
  test_bpftool_synctypes.py:319: SyntaxWarning: invalid escape sequence '\w'
    pattern = re.compile('([\w-]+) ?(?:\||}[ }\]"])')
  test_bpftool_synctypes.py:341: SyntaxWarning: invalid escape sequence '\|'
    start_marker = re.compile('\|COMMON_OPTIONS\| replace:: {')
  test_bpftool_synctypes.py:342: SyntaxWarning: invalid escape sequence '\*'
    pattern = re.compile('\*\*([\w/-]+)\*\*')

Escaping them clears out the warnings.

  $ tools/testing/selftests/bpf/test_bpftool_synctypes.py; echo $?
  0

Signed-off-by: Ariel Otilibili <ariel.otilibili-anieli@eurecom.fr>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Tested-by: Quentin Monnet <qmo@kernel.org>
Reviewed-by: Quentin Monnet <qmo@kernel.org>
Link: https://docs.python.org/3/library/re.html
Link: https://lore.kernel.org/bpf/20241211220012.714055-2-ariel.otilibili-anieli@eurecom.fr