[SandboxVectorizer] Use sbvec-passes flag to create a pipeline of Region passes after BottomUpVec. (#111223)

The main change is that the main SandboxVectorizer pass no longer has a
pipeline of function passes. Now it is a wrapper that creates sandbox IR
from functions before calling BottomUpVec.

BottomUpVec now builds its own RegionPassManager from the `sbvec-passes`
flag, using a PassRegistry.def file. For now, these region passes are
not run (BottomUpVec doesn't create Regions yet), and only a null pass
for testing exists.

This commit also changes the ownership model for sandboxir::PassManager:
instead of having a PassRegistry that owns passes, and PassManagers that
contain non-owning pointers to the passes, now PassManager owns (via
unique pointers) the passes it contains.

PassRegistry is now deleted, and the logic to parse and create a pass
pipeline is now in PassManager::setPassPipeline.

0 files changed, 0 insertions, 0 deletions