Report issues with loading summaries using LibraryCycleLinkException.

...so that we can include additional data as a "file".
The exception text has smaller size limit than we need.

Change-Id: I56ff7f7a85658419aa360bd6ab48b55fd180bfe5
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/148794
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

Author: scheglov

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

@@ -166,15 +166,18 @@ class LibraryContext {
                   var existingSource = existingElement?.source;
                   var libraryRefs = elementFactory.rootReference.children;
                   var libraryUriList = libraryRefs.map((e) => e.name).toList();
-                  throw StateError(
-                    '[The library is already loaded]'
-                    '[oldUri: ${existingSource.uri}]'
-                    '[oldPath: ${existingSource.fullName}]'
-                    '[newUri: ${libraryFile.uriStr}]'
-                    '[newPath: ${libraryFile.path}]'
-                    '[cycle: $cycle]'
-                    '[loadedBundles: ${loadedBundles.toList()}]'
-                    '[elementFactory.libraries: $libraryUriList]',
+                  var statusText = '[The library is already loaded]'
+                      '[oldUri: ${existingSource.uri}]'
+                      '[oldPath: ${existingSource.fullName}]'
+                      '[newUri: ${libraryFile.uriStr}]'
+                      '[newPath: ${libraryFile.path}]'
+                      '[cycle: $cycle]'
+                      '[loadedBundles: ${loadedBundles.toList()}]'
+                      '[elementFactory.libraries: $libraryUriList]';
+                  throw LibraryCycleLinkException(
+                    'Cycle loading state error',
+                    StackTrace.current,
+                    {'status': statusText},
                   );
                 }
               }