Explicitly State Behavior when Host Pointer is freed after clCreateBuffer

The specification does not state the behavior if `clCreateBuffer` is called with `CL_MEM_USE_HOST_PTR` and then the host pointer is freed in the memory flags, clCreateBuffer, or clCreateBufferWithProperties sections. Should it be added for explicitness and since the behavior would most likely be undefined?

Read the CL_MEM_USE_HOST_PTR memory-flags, clCreateBuffer, and clCreateBufferWithProperties sections named in the issue. Compare related pointer-lifetime wording elsewhere in the specification and confirm the intended behavior with maintainers. Done when the relevant sections explicitly describe what happens if the host pointer is freed.

Written by the indexing model from the issue text.