Codegen: Selectively copy in array addresses for OpenMP code

The detection of values that need to be copied in to the generated OpenMP
subfunction also detects the array base addresses needed in the SCoP. Hence, it
is not necessary to unconditionally copy all the base addresses to the generated
function.

Test cases are modified to reflect this change. Arrays which are global
variables do not occur in the struct passed to the subfunction anymore. A test
case for base address copy-in is added in copy_in_array.{c,ll}.

Committed with slight modifications

Contributed by:  Armin Groesslinger <armin.groesslinger@uni-passau.de>

llvm-svn: 167215