Variables resolve incorrectly with try catch statements

Minimal repro input:

```php
try {
  $foo = 1;
} catch (Exception $e) {
  $foo = 2;
}
echo $foo;
```
produces
```php
try {
  $foo = 1;
} catch (Exception $e) {
  $foo = 2;
}
echo 2;
```

I believe `Resolver->nodeCanBranch` needs to include try catch statements as well.