[ms-abi] Makes Virtual Base Alignment Look at All Virtual Bases

Prior to this patch, the alignment imposed by virtual bases only 
included direct virtual bases.  This patch fixes it to look at all 
virtual bases.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@196997 91177308-0d34-0410-b5e6-96231b3b80d8