#2145. Add more local variable declaration tests

[sgrekhov]

No description provided.

[eernstg]

Looks good! Noted a couple of typos. Also, I think the tests can be a bit stronger when it comes to variables whose static type is an intersection type.

[eernstg]

That isn't quite accurate: The local declaration introduces the name into the enclosing scope from the beginning of that scope:

var x = 1;

void main() {
  print(x); // Error (`x` is the local variable below, not the top-level variable).
  var x = true;
}

But it is true that we can't use that name (it's a compile-time error no matter how we use it) before the end of the initializing expression in the declaration of that name.

[sgrekhov]

Tests updated. Please review

[eernstg]

LGTM!