[OpenCL] Forbid size dependent types used as kernel arguments

Summary:
Size_t, intptr_t, uintptr_t and ptrdiff_t cannot be used as kernel
arguments, according to OpenCL Specification s6.9k:
The size in bytes of these types are implementation-defined and in
addition can also be different for the OpenCL device and the host
processor making it difficult to allocate buffer objects to be passed
as arguments to a kernel declared as pointer to these types.

Patch by: Andrew Savonichev

Reviewers: Anastasia, yaxunl

Subscribers: yaxunl, Anastasia, cfe-commits

Differential Revision: https://reviews.llvm.org/D49725

llvm-svn: 338432