Fix NPE in tests.

TBR

R=brianwilkerson@google.com
BUG=

Review URL: https://codereview.chromium.org//846383004

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@42937 260f80e4-7a28-3924-810f-c04153c831b5

pkg/analysis_server/test/analysis_server_test.dart

@@ -284,6 +284,7 @@ import "../foo/foo.dart";
     notice.setErrors([], new LineInfo([0]));
     AnalysisResult firstResult = new AnalysisResult([notice], 0, '', 0);
     AnalysisResult lastResult = new AnalysisResult(null, 1, '', 1);
+    when(context.analysisOptions).thenReturn(new AnalysisOptionsImpl());
     when(
         context.performAnalysisTask).thenReturnList(
             [firstResult, firstResult, firstResult, lastResult]);