Fixes #24554, where it was noted that currently comparing a masked structured array with an unmasked one fails:

import numpy as np
a = np.array([(1., 2.), (3., 4.)], "f8,f8")
ma = np.ma.MaskedArray(a)
ma == a
# TypeError: Cannot compare structured or void to non-void arrays.

While looking at the code, it seemed obvious that a correction to the mask shape done inside an if statement should really be outside. A quick test confirmed that. So, the second commit fixes that too. I can make it 2 PRs if need be (but am trying to just be done...)

Not sure about the milestone. I put 1.26.0, but that may be too late. This definitely is not very urgent, since the bug has been there for years.