[sil-opt] Only notify the pass manager of newly added functions in SILOptFunctionBuilder.

To do so this commit does a few different things:

1. I changed SILOptFunctionBuilder to notify the pass manager's logging
functionality when new functions are added to the module and to notify analyses
as well. NOTE: This on purpose does not put the new function on the pass manager
worklist since we do not want to by mistake introduce a large amount of
re-optimizations. Such a thing should be explicit.

2. I eliminated SILModuleTransform::notifyAddFunction. This just performed the
operations from 1. Now that SILOptFunctionBuilder performs this operation for
us, it is not needed.

3. I changed SILFunctionTransform::notifyAddFunction to just add the function to
the passmanager worklist. It does not need to notify the pass manager's logging
or analyses that a new function was added to the module since
SILOptFunctionBuilder now performs that operation. Given its reduced
functionality, I changed the name to addFunctionToPassManagerWorklist(...). The
name is a little long/verbose, but this is a feature since one should think
before getting the pass manager to rerun transforms on a function. Also, giving
it a longer name calls out the operation in the code visually, giving this
operation more prominance when reading code. NOTE: I did the rename using
Xcode's refactoring functionality!

rdar://42301529

lib/SILOptimizer/Transforms/Devirtualizer.cpp

@@ -103,7 +103,7 @@ bool Devirtualizer::devirtualizeAppliesInFunction(SILFunction &F,
     // be beneficial to rerun some earlier passes on the current
     // function now that we've made these direct references visible.
     if (CalleeFn->isDefinition() && CalleeFn->shouldOptimize())
-      notifyAddFunction(CalleeFn, nullptr);
+      addFunctionToPassManagerWorklist(CalleeFn, nullptr);
   }
 
   return Changed;