strange handling of variables in assume

[vit-tucek]

Sometimes it is ok to refer to a variable via string, sometimes it's not. Depends on the kind of assumption.

var('a b')
assume('a', a > 1)
assume(a, "integer")
assume('b', b > 1)
assume('b', "integer")
assumptions()

(a, b)
[a > 1, a is integer, b > 1]

CC: @rwst @egourgoulhon

Component: symbolics

Issue created by migration from https://trac.sagemath.org/ticket/24392

[mkoeppe]

comment:4

Setting new milestone based on a cursory review of ticket status, priority, and last modification date.