ralloc: use rzalloc where it's necessary

ralloc: use rzalloc where it's necessary

No change in behavior. ralloc_size is equivalent to rzalloc_size.
That will change though.

Calls not switched to rzalloc_size:
- ralloc_vasprintf
- glsl_type::name allocation (it's filled with snprintf)
- C++ classes where valgrind didn't show uninitialized values

I switched most of non-glsl stuff to rzalloc without checking whether
it's really needed.

Reviewed-by: Edward O'Callaghan <funfunctor@folklore1984.net>
Tested-by: Edmondo Tommasina <edmondo.tommasina@gmail.com>
Reviewed-by: Nicolai Hähnle <nicolai.haehnle@amd.com>