[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

llvm-svn: 369251