Simplify test/CodeGenCXX/microsoft-abi-vtables-virtual-inheritance.cpp by forcing VFTableBuilder invocation with virtual function calls or constructors codegen

Previously the vftables were built at the end of the TU in a reverse-to-random order

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@204567 91177308-0d34-0410-b5e6-96231b3b80d8