handle namespacing of primitives
Summary:
Bless a list of primitives so readonly checks pass in Hackc.
Just like in `parser/readonly_check.rs`, used in prod, we allow returning a value as some_primitive_type as mutable even when the value is readonly. Easiest to explain via the snapshot test: `primitives_namespacing.php` in
D38462806.
## Why:
The readonly checking in `parser/readonly_check.rs` expects primitives to look like this: `int`.
But in hackc, we are seeing types after `elaborate_namespace_visitor`, which changes `int` to `\HH\int`.
Reviewed By: aorenste
Differential Revision:
D38579242
fbshipit-source-id:
491c53de71e8849301497b88027bfff115f09b37