When laying out bases in, always try the "base subobject" LLVM type. If it

When laying out bases in, always try the "base subobject" LLVM type. If it
turns out that a field or base needs to be laid out in the tail padding of
the base, CGRecordLayoutBuilder::ResizeLastBaseFieldIfNecessary will convert
it to an array of i8.

I've audited the new test results to make sure that they are still valid. I've
also verified that we pass a self-host with this change.

This (finally) fixes PR5589!

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@129673 91177308-0d34-0410-b5e6-96231b3b80d8