Stop using RESOLVED_UNIT_x for other libraries.

pkg/analysis_server/lib/src/analysis_server.dart

Index: pkg/analysis_server/lib/src/analysis_server.dart
diff --git a/pkg/analysis_server/lib/src/analysis_server.dart b/pkg/analysis_server/lib/src/analysis_server.dart
index 5d3cecfd1d400311893d3a90c65b2379ff98f549..f0d7931c369bfa78eef8e45c9e57a87354024047 100644
--- a/pkg/analysis_server/lib/src/analysis_server.dart
+++ b/pkg/analysis_server/lib/src/analysis_server.dart
@@ -1331,7 +1331,7 @@ class AnalysisServer {
     }
     // if library has not been resolved yet, the unit will be resolved later
     Source librarySource = librarySources[0];
-    if (context.getResult(librarySource, LIBRARY_ELEMENT8) == null) {
+    if (context.getResult(librarySource, LIBRARY_ELEMENT5) == null) {
       return null;
     }
     // if library has been already resolved, resolve unit