[analyzer] Hotfix a boolean conversion crash in the Z3 SMTConv (#158276)

If a UnarySymExpr with an arithmetic negation of a logical operation to
obtain a SMTRefExpr, the Z3 engine will crash. Since an arithmetic
negation of a logical operation makes no sense and has no effect, the
arithmetic negation is detected and removed to avoid the crash in Z3.

This shows up following this C snippet

```c++
1: void bb(int a) {
2:  if (-(&c && a)) {
3:     int *d;
4:     *d; // expected-warning{{Dereference of undefined pointer value}}
5:  }
6: }
```

Line 2 is expressed as SymExpr -((reg_$1<int a>) != 0) , which is then
attempted to be converted to SMTRefExpr (not (= reg_$1 #x00000000)).
This does not make sense to Z3 since a logical expression cannot be
arithmetically negated.

A solution is to detect that the result of a comparison is attempted to
be arithmetically negated and remove that arithmetic negation since the
negation of a bool is the same as the positive of a bool. Bool's have no
sign, they are only True or False.

Co-authored-by: Vince Bridgers <vince.a.bridgers@ericsson.com>