Fix monty imports, enhance test for Outcar parser to cover uncompressed format

[DanielYang59]

Summary

• Test monty fix for reverse readline, to close Outcar class returns empty magnetization attribute when parsing OUTCAR file on Windows operating system #4033
• Replace reverse_readline with faster reverse_readfile
• Fix incorrect monty imports
• Enhance unit test for reported Outcar parser (need to test unzipped format):

  pymatgen/tests/io/vasp/test_outputs.py

  Lines 802 to 823 in 60464fd

  	def test_init(self):
  	outcar = Outcar(f"{VASP_OUT_DIR}/OUTCAR.gz")
  	expected_mag = (
  	{"d": 0.0, "p": 0.003, "s": 0.002, "tot": 0.005},
  	{"d": 0.798, "p": 0.008, "s": 0.007, "tot": 0.813},
  	{"d": 0.798, "p": 0.008, "s": 0.007, "tot": 0.813},
  	{"d": 0.0, "p": -0.117, "s": 0.005, "tot": -0.112},
  	{"d": 0.0, "p": -0.165, "s": 0.004, "tot": -0.162},
  	{"d": 0.0, "p": -0.117, "s": 0.005, "tot": -0.112},
  	{"d": 0.0, "p": -0.165, "s": 0.004, "tot": -0.162},
  	)
  	expected_chg = (
  	{"p": 0.154, "s": 0.078, "d": 0.0, "tot": 0.232},
  	{"p": 0.707, "s": 0.463, "d": 8.316, "tot": 9.486},
  	{"p": 0.707, "s": 0.463, "d": 8.316, "tot": 9.486},
  	{"p": 3.388, "s": 1.576, "d": 0.0, "tot": 4.964},
  	{"p": 3.365, "s": 1.582, "d": 0.0, "tot": 4.947},
  	{"p": 3.388, "s": 1.576, "d": 0.0, "tot": 4.964},
  	{"p": 3.365, "s": 1.582, "d": 0.0, "tot": 4.947},
  	)
  	assert outcar.magnetization == approx(expected_mag, abs=1e-5), "Wrong magnetization read from Outcar"