Reland [LegacyPM] Remove some legacy passes

These are part of the optimization pipeline, of which the legacy pass manager version is deprecated.

Namely
* Internalize
* StripSymbols
* StripNonDebugSymbols
* StripDeadDebugInfo
* StripDeadPrototypes
* VectorCombine
* WarnMissedTransformations

Fixed previously failing ocaml tests (one of them seems to already be failing?)