[Polly] Add support for -polly-dump-before(-file) with the NPM.

Only supported with -polly-position=early. Unfortunately, the
extension point callpack for VectorizerStart only passes a
FunctionPassManager, making it impossible to add a module pass.

GitOrigin-RevId: 29bef8e4e3593ab37c4d3b6289dcdec961c3fb52
5 files changed