BUG: savez raises exception for masked arrays

[jpbianchi]

Resolves #18134
savez() now raises an exception for a masked array, like save() already did.
Tests were added for both functions to test the exception being raised in case a masked array is passed as argument.

[HaoZeke]

Almost there :)

[HaoZeke]

Passes the new test.

[HaoZeke]

This will now break the tests depending on this tuple. e.g.:

__________________________ test_compressed_roundtrip ___________________________

tmpdir = local('/tmp/pytest-of-runner/pytest-0/test_compressed_roundtrip0')

    def test_compressed_roundtrip(tmpdir):
        arr = np.random.rand(200, 200)
        npz_file = os.path.join(tmpdir, 'compressed.npz')
>       np.savez_compressed(npz_file, arr=arr)

arr        = array([[0.75950489, 0.26798953, 0.83152339, ..., 0.907[3414](https://github.com/numpy/numpy/actions/runs/3609969600/jobs/6083480553#step:4:3418)2, 0.76341456,
        0.41962783],
       [0.71932335, 0.65...59,
        0.22654725],
       [0.17476853, 0.4739831 , 0.52077257, ..., 0.97867451, 0.50465821,
        0.2018301 ]])
npz_file   = '/tmp/pytest-of-runner/pytest-0/test_compressed_roundtrip0/compressed.npz'
tmpdir     = local('/tmp/pytest-of-runner/pytest-0/test_compressed_roundtrip0')

../../builds/venv/lib/python3.8/site-packages/numpy-1.25.0.dev0+109.g713be80dd-py3.8-linux-x86_64.egg/numpy/lib/tests/test_format.py:497:

[HaoZeke]

Other examples:

Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
ValueError: I/O operation on closed file.
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
ValueError: I/O operation on closed file.
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/tempfile.py", line 473, in func_wrapper
    return func(*args, **kwargs)
ValueError: seek of closed file
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
ValueError: I/O operation on closed file.
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
ValueError: I/O operation on closed file.
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>
Traceback (most recent call last):
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1821, in __del__
    self.close()
  File "/opt/hostedtoolcache/Python/3.8.14/x64/lib/python3.8/zipfile.py", line 1838, in close
    self.fp.seek(self.start_dir)
ValueError: I/O operation on closed file.
Exception ignored in: <function ZipFile.__del__ at 0x7fc089e4d1f0>

[jpbianchi]

The first error comes from the fact that, after my change, the zipfile type is checked by "if isfileobj(fp)", and then the command 'array.tofile()' is executed, which was not the case before.
I found out that that instruction works for maskedarrays, but NOT for arrays (which is what the test 'test_compressed_roundtrip' uses).
I've reproduced the issue by stopping the debugger at that instruction, and tested both arrays and masked_arrays, and you can see that arrays give an error about using fileno() while masked_arrays give the exception we want.
debugger screenshot