This patch enables explicit generation of TBAA information in all cases where LValue base info is propagated or constructed in non-trivial ways. Eventually, we will consider each of these cases to make sure the TBAA information is correct and not too conservative. For now, we just fall back to generating TBAA info from the access type.
This patch should not bring in any functional changes.
This is part of D38126 reworked to be a separate patch to simplify review.