Rename the global inference task and reduce it's API surface by introducing the

tests/compiler/dart2js/mirror_final_field_inferrer_test.dart

Index: tests/compiler/dart2js/mirror_final_field_inferrer_test.dart
diff --git a/tests/compiler/dart2js/mirror_final_field_inferrer_test.dart b/tests/compiler/dart2js/mirror_final_field_inferrer_test.dart
index 54252ec8d0ca889856784e1791439d842851147e..7663d51fe92c5293429f68bb5474316f753a7144 100644
--- a/tests/compiler/dart2js/mirror_final_field_inferrer_test.dart
+++ b/tests/compiler/dart2js/mirror_final_field_inferrer_test.dart
@@ -28,9 +28,9 @@ void main() {
     var result = await runCompiler(memorySourceFiles: MEMORY_SOURCE_FILES);
     var compiler = result.compiler;
     var element = findElement(compiler, 'field');
-    var typesTask = compiler.typesTask;
-    var typesInferrer = typesTask.typesInferrer;
-    Expect.equals(typesTask.uint31Type,
+    var commonMasks = compiler.commonMasks;
+    var typesInferrer = compiler.globalInference.typesInferrer;
+    Expect.equals(commonMasks.uint31Type,
                   simplify(typesInferrer.getTypeOfElement(element), compiler),
                   'field');
   });