[ms-abi] 64-bit fixes for r196549

In order to address latent bugs that were easier to expose in 64-bit 
mode, we move the application of __declspec(align) to before the layout 
of vbases rather than after.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196861 91177308-0d34-0410-b5e6-96231b3b80d8