metaticket for simon_two_descent issues

[cremona]

There are several open tickets relating to issues with the simon_two_descent function for elliptic curves over Q and over number fields, which call Denis Simon's GP scripts, as well as a similar number of closed tickets. To help keep track of these, this ticket serves only to be a catalogue of these open tickets in order to better coordinate work on them.

#5153 bug in simon_two_descent for elliptic curves [fixed]

#9322 long time in simon_two_descent for elliptic curves [needs work]

#10735 Simon 2-descent only returns an upper bound on the 2-Selmer rank [needs review (documentation), upstream]

#10745 bug in elliptic curve gens() [needs info]

#11005 Update Simon's GP scripts [fixed]

#15809 Compile Denis Simon's scripts with gp2c [new]

#13593 tighter upper bound on elliptic curve rank [fixed]

#15483 Simon 2-descent gives RuntimeError for an elliptic curve over a quadratic field [fixed (workaround), upstream]

#16022 simon_two_descent sometimes gives wrong answers [needs review, upstream]

Upstream are the ones with bugs in the script that were reported to the author.