sys/fuchsia: add test for vmar syscall descriptions

Also made some small updates to the vmar descriptions:
- In a few places, a `len` arg was incorrectly tagged as the length
  of another arg when it actually represents a region size; fixed.
- The `buffer` and `buffer_size` args to `zx_vmar_op_range` must
  be null; replaced with constants.
- Added a `zx_vaddr` resource type wrapping `intptr` and used it
  in place of `vma`, since it's not clear how to use `vma` as the
  pointee type of an outptr in a program.

0 files changed, 0 insertions, 0 deletions