[OpenCL] Improve extension-version.cl and to_addr_builtin.cl tests

Add cl_khr_depth_images to extension-version.cl.

Extend to_addr_builtin.cl to additionally test the built-in methods
to_private and to_local, and test assignment with to_global to
incorrect types.

Patch by Alistair Davies.

Differential Revision: https://reviews.llvm.org/D52020

llvm-svn: 343207