Add alignment to basic blocks.

A further CL will plumb this into the block builder.

BUG=

Review URL: https://codereview.appspot.com/6822076

git-svn-id: http://sawbuck.googlecode.com/svn/trunk/syzygy@1218 15e8cca8-e42c-11de-a347-f34a4f72eb7d
8 files changed