There's only one method for which the ProjectAnalyzer actually gets used - SourceManager.GetManifestAndLock(). There's really no reason that it has to be injected into the source manager as an argument to NewSourceManager(); it could just be passed as a parameter to that one method.

In addition to cleaning up some internal interfaces, the big advantage here is that a *sourceMgr instance is no longer bound to operate with a single ProjectAnalyzer. There's no current use case where this really matters right now, but this was a nasty coupling between solvers (whose correct operation is predicated on only ever having the one analyzer) and the source managers.

We can also eliminate SourceManager.AnalyzerInfo() as part of this.