Fix assert constructor initializer tests.

pkg/analyzer/lib/src/dart/analysis/file_state.dart

Index: pkg/analyzer/lib/src/dart/analysis/file_state.dart
diff --git a/pkg/analyzer/lib/src/dart/analysis/file_state.dart b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
index 1608c33fe85796916ebbc7f44f55a77da3afcb5c..ba54b8bb17031d53d0de4c949ec3743dd1ac4de4 100644
--- a/pkg/analyzer/lib/src/dart/analysis/file_state.dart
+++ b/pkg/analyzer/lib/src/dart/analysis/file_state.dart
@@ -340,6 +340,7 @@ class FileState {
     LineInfo lineInfo = new LineInfo(scanner.lineStarts);
 
     Parser parser = new Parser(source, errorListener);
+    parser.enableAssertInitializer = analysisOptions.enableAssertInitializer;
     parser.parseGenericMethodComments = analysisOptions.strongMode;
     CompilationUnit unit = parser.parseCompilationUnit(token);
     unit.lineInfo = lineInfo;