BUG: int32 and intc should both appear in sctypes

[mattip]

Fix issue #26439 where in 32-bit builds np.int32 did not appear in sctypes, so np.isdtype(np.int32, 'integral') was False.

The issue was that

[t.type for t in set(typeinfo.values())]

is not the same as

set([t.type for t in typeinfo.values()])

The latter has more members, and is the one used now.

[ngoldbaum]

CI failures look unrelated (not sure why installing g++-13 decided to suddenly stop working on Ubuntu 22.04).

This looks correct to me and thanks for adding a test. Subtle issue...

[charris]

Thanks Matti.

CI is becoming annoying.