Revert "Report error if the same uri appears in multiple summaries."

pkg/analyzer_cli/lib/src/build_mode.dart

Index: pkg/analyzer_cli/lib/src/build_mode.dart
diff --git a/pkg/analyzer_cli/lib/src/build_mode.dart b/pkg/analyzer_cli/lib/src/build_mode.dart
index 985511db795d58c303585312c7a6a99c3d020c48..0fa7fa6d64e65beeb5cc8eeb0878d222d52d738b 100644
--- a/pkg/analyzer_cli/lib/src/build_mode.dart
+++ b/pkg/analyzer_cli/lib/src/build_mode.dart
@@ -169,13 +169,7 @@ class BuildMode {
         .toList());
 
     // Prepare the analysis context.
-    try {
-      _createContext();
-    } on ConflictingSummaryException catch (e) {
-      errorSink.writeln('$e');
-      io.exitCode = ErrorSeverity.ERROR.ordinal;
-      return ErrorSeverity.ERROR;
-    }
+    _createContext();
 
     // Add sources.
     ChangeSet changeSet = new ChangeSet();