Get astBuilder and typeInferenceEngine from SourceLoader.

pkg/front_end/lib/src/fasta/source/source_loader.dart

Index: pkg/front_end/lib/src/fasta/source/source_loader.dart
diff --git a/pkg/front_end/lib/src/fasta/source/source_loader.dart b/pkg/front_end/lib/src/fasta/source/source_loader.dart
index 88475b339d798bd1711f6557bb84546d28ea816b..699ab43c7728fe42a10d9434ea3c54604510decc 100644
--- a/pkg/front_end/lib/src/fasta/source/source_loader.dart
+++ b/pkg/front_end/lib/src/fasta/source/source_loader.dart
@@ -391,7 +391,7 @@ class SourceLoader<L> extends Loader<L> {
     typeInferenceEngine.prepareTopLevel(coreTypes, hierarchy);
     builders.forEach((Uri uri, LibraryBuilder library) {
       if (library is SourceLibraryBuilder) {
-        library.prepareInitializerInference(typeInferenceEngine, library, null);
+        library.prepareInitializerInference(library, null);
       }
     });
     ticker.logMs("Prepared initializer inference");