test(parse): Test for the parsing not invoking twice to get self

New tests to not call twice a function to get self
fix(parse): Fix context access and double function call

Fix a context duplication and invocation to a previous context when
doing an access modifier function on the result of a function
Currently, when doing `foo().bar()`, `foo` is called twice, the first
time to get the context and the second one for `bar` to get the
underlying object. Then the call to `bar` is called using the second
instance as self
This is equivalent to doing:
```
var instance1 = foo();
var instance2 = foo();
instance2.bar.apply(instance1);
```

Closes #2496