Properly handle all kinds of variable in arguments of or (||)

[PaulKlint]

Describe the bug

Simple variable declarations in or expressions are handled properly: int x := 1 || int x := 2 is ok and does not produce a double declaration error for x.

To Reproduce
The following examples all give a double declaration error for x:

• value main() = {*int x} := {1,2,3} || {*int x} := {10,20,30};
• value main() = [+int x] := [1,2,3] || [+int x] := [10,20,30];
• value main() = [*int x] := [1,2,3] || [*int x] := [10,20,30];
• value main() = [+int x] := [1,2,3] || [+int x] := [10,20,30];
• value main() = [int x: 1] := [1] || [int x: 10] := [10];

Expected behavior
All the above examples are acceptable and should not generate an error