Add top level type inference logic for integer literals.

pkg/front_end/test/subpackage_relationships_test.dart

Index: pkg/front_end/test/subpackage_relationships_test.dart
diff --git a/pkg/front_end/test/subpackage_relationships_test.dart b/pkg/front_end/test/subpackage_relationships_test.dart
index 968aa2418af69c9d3bd7ac153e8f8ee067fb3e80..9c7cacae125bc0b77ef00d43015be7b662d80f5e 100644
--- a/pkg/front_end/test/subpackage_relationships_test.dart
+++ b/pkg/front_end/test/subpackage_relationships_test.dart
@@ -55,6 +55,7 @@ final subpackageRules = {
     'lib/src/fasta',
     'lib/src/fasta/parser',
     'lib/src/fasta/source',
+    'lib/src/fasta/type_inference',
     'lib/src/fasta/util',
   ]),
   'lib/src/fasta/dill': new SubpackageRules(allowedDependencies: [
@@ -105,6 +106,7 @@ final subpackageRules = {
     'lib/src/fasta/scanner',
   ]),
   'lib/src/fasta/type_inference': new SubpackageRules(allowedDependencies: [
+    'lib/src',
     'lib/src/base',
   ]),
   'lib/src/fasta/util': new SubpackageRules(),