[clang] [analyzer][solver] On SymSym RelOps, check EQClass members for contradictions (PR #71284)

[Balazs Benics via cfe-commits]

steakhal wrote:

For crossreference: I raised some related questions around having void casts artificially keeping constraints and symbols alive at discuss:
https://discourse.llvm.org/t/range-based-solver-and-eager-symbol-garbage-collection/74670

https://github.com/llvm/llvm-project/pull/71284