Failing OpenCL vector traits due to address spaces

many vector traits seem to have issues is used with address spaces deduced.

Here is an example:

```
int4 v;
static_assert(std::vector_size::value==4); // This fails because v is '__provate int4' and not 'int4'
```

To make them work we need to add `remove_address_space` trait everywhere. Could we reduce such verbosity by providing extra specializations of such traits? We can probably do it universally for all qualifiers and add a description as a rule:

`any top level qualifier provided with type T is ignored/stripped out before ...`

Start by locating the vector trait implementations and the existing remove_address_space trait. Use the int4 example to check how deduced address spaces affect std::vector_size and related traits. Done means the relevant traits handle top-level address-space qualifiers consistently, with the rule documented as requested.

Written by the indexing model from the issue text.