assignment_to_final_local interaction with try/catch

In the following code, `x` can only be set once, but the second assignment is considered an error.

```dart
void main() {
final int x;
try {
// thow 'test';
x = 1;
} catch {
x = 2; // The final variable 'x' can only be set once.
}
print(x);
}
```

I think if the assignment is the last statement in a try block, it should not be considered to conflict with an assignment in a catch block.

Start by reproducing the Dart example and reading the language rules for final-variable assignment across try/catch control flow. Done would require a project decision on the expected behavior and corresponding language specification and test coverage; no repository files or tests are named in the issue.

Written by the indexing model from the issue text.