[OpenCL] Fix an infinite loop in builidng AddrSpaceQualType (#92612)

In building AddrSpaceQualType
(https://github.com/llvm/llvm-project/pull/90048), there is a bug in
removeAddrSpaceQualType() for arrays. Arrays are weird because
qualifiers on the element type also count as qualifiers on the type, so
getSingleStepDesugaredType() can't remove the sugar on arrays. This
results in an infinite loop in removeAddrSpaceQualType. To fix the
issue, we use ASTContext::getUnqualifiedArrayType instead, which strips
the qualifier off the element type, then reconstruct the array type.