[PECOFF] Align section contents as specified by the object file's section header.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@190120 91177308-0d34-0410-b5e6-96231b3b80d8
[PECOFF] Add /machine command line option.

git-svn-id: https://llvm.org/svn/llvm-project/lld/trunk@190121 91177308-0d34-0410-b5e6-96231b3b80d8