[mach-o] generate LC_DATA_IN_CODE in final linked images

lld was regenerating LC_DATA_IN_CODE in .o output files, but not into
final linked images.

Update test case to verify data-in-code info makes it into final linked images.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@220827 91177308-0d34-0410-b5e6-96231b3b80d8