don't produce errors from inference for downward inferred type variables

pkg/analyzer/test/generated/strong_mode_test.dart

Index: pkg/analyzer/test/generated/strong_mode_test.dart
diff --git a/pkg/analyzer/test/generated/strong_mode_test.dart b/pkg/analyzer/test/generated/strong_mode_test.dart
index ccc5aef754b0a1e41acbc9a8022c9ca0c2f69be3..e8ce3e5216ac281be99191a0dd602bc21db4a89d 100644
--- a/pkg/analyzer/test/generated/strong_mode_test.dart
+++ b/pkg/analyzer/test/generated/strong_mode_test.dart
@@ -1661,8 +1661,7 @@ class StrongModeLocalInferenceTest extends ResolverTestCase {
    ''';
     Source source = addSource(code);
     TestAnalysisResult analysisResult = await computeAnalysisResult(source);
-    assertErrors(source,
-        [StrongModeCode.COULD_NOT_INFER, StrongModeCode.INVALID_CAST_LITERAL]);
+    assertErrors(source,[StrongModeCode.INVALID_CAST_LITERAL]);
     verify([source]);
     CompilationUnit unit = analysisResult.unit;
     FunctionDeclaration test = AstFinder.getTopLevelFunction(unit, "test");
@@ -1714,7 +1713,6 @@ class StrongModeLocalInferenceTest extends ResolverTestCase {
     Source source = addSource(code);
     TestAnalysisResult analysisResult = await computeAnalysisResult(source);
     assertErrors(source, [
-      StrongModeCode.COULD_NOT_INFER,
       StrongModeCode.INVALID_CAST_LITERAL,
     ]);
     verify([source]);