Trac #30805: Fix doctest errors/segfaults with system FLINT 2.6 (monsky_washnitzer)

As reported in https://groups.google.com/d/msg/sage-
release/PByUmh8WuIM/NzB6gNkpAwAJ (and similar)

this leads to "Killed due to abort" for example on `debian-testing`.

Also on `ubuntu-groovy-standard`
(https://github.com/sagemath/sage/runs/1270680095)

We carve out a patch from #29719 to make it work

Blocker for 9.2 because it gives a segfault.

URL: https://trac.sagemath.org/30805
Reported by: mkoeppe
Ticket author(s): Dima Pasechnik
Reviewer(s): Matthias Koeppe

Author: Release Manager

build/pkgs/configure/checksums.ini

@@ -1,4 +1,4 @@
 tarball=configure-VERSION.tar.gz
-sha1=f724be3bb37dd71f5b07dc1b4542a4ad23461e47
-md5=2a25fb97ee7e9c9eaa85cdc6e1082a2e
-cksum=1804502685
+sha1=5061e9d40e35c0c9247e61a3f80b664e9c8e8b5e
+md5=9d0278359e22b8b27dc27ce944f7301e
+cksum=1135010098

build/pkgs/configure/package-version.txt

@@ -1 +1 @@
-70d165564b827f40db047c1ce0f18aed56c4ad1b
+afc935a952e5aa5afd89acc39bac645b71768813

src/sage/schemes/hyperelliptic_curves/monsky_washnitzer.py

@@ -1876,9 +1876,9 @@ def __init__(self, Q, R=None, invert_y=True):
             if not hasattr(self, '_curve'):
                 if self._Q.degree() == 3:
                     ainvs = [0, self._Q[2], 0, self._Q[1], self._Q[0]]
-                    self._curve = EllipticCurve(ainvs)
+                    self._curve = EllipticCurve(ainvs, check_squarefree=R.is_field())
                 else:
-                    self._curve = HyperellipticCurve(self._Q)
+                    self._curve = HyperellipticCurve(self._Q, check_squarefree=R.is_field())
 
         else:
             raise NotImplementedError("Must be an elliptic curve or polynomial "