gh-41287: Improve normalization and inverse handling for Laurent Polynomials
Fix #41282
1. `has_inverse_of(i)` called `_normalize(i)` which mutated self, even
though it should be a read-only query
2. `_normalize(i)` had a bug: it divided `_poly` by `gen(i)` once
instead of by `gen(i)**e`
3. `has_any_inverse()` only checked `_mon` without considering if the
representation was non-normalized
4. `__call__` evaluated `_poly` directly, which gave wrong results for
non-normalized representations
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URL: https://github.com/sagemath/sage/pull/41287
Reported by: Chenxin Zhong
Reviewer(s): Travis Scrimshaw
