swift

28e7e952 - [mandatory-combine] Put canonicalization and trivial DCE behind a flag so I can use it for writing OSSA RAUW tests.

[mandatory-combine] Put canonicalization and trivial DCE behind a flag so I can use it for writing OSSA RAUW tests. I am going to loop back around and enable this all the time, but this is seeming to disturb codegen more than expected, so I am going to enable it everywhere later (since it is not my primary goal).