[OpenCL] Fix addr space deduction for pointers/references to arrays.

[OpenCL] Fix addr space deduction for pointers/references to arrays.

Rewrite the logic for detecting if we are deducing addr space of
a pointee type to take into account special logic for arrays. For
pointers/references to arrays we can have any number of parentheses
expressions as well as nested pointers.

Differential Revision: https://reviews.llvm.org/D66137

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@369251 91177308-0d34-0410-b5e6-96231b3b80d8