Allow ambiguous Expect and ExpectException imports.

sdk/lib/_internal/compiler/implementation/elements/modelx.dart

Index: sdk/lib/_internal/compiler/implementation/elements/modelx.dart
diff --git a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
index f00794640c29ca5c5686cd2b564c5f84c57f4ef0..f53bfef7645801e01fec468437cbe4f993c7f7aa 100644
--- a/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
+++ b/sdk/lib/_internal/compiler/implementation/elements/modelx.dart
@@ -600,6 +600,11 @@ class LibraryElementX extends ElementX implements LibraryElement {
   void addImport(Element element, DiagnosticListener listener) {
     Element existing = importScope[element.name];
     if (existing != null) {
+      // TODO(8474): Remove the "Expect" special casing.
+      if (element.name == const SourceString("Expect") ||
+          element.name == const SourceString("ExpectException")) {
+        return;
+      }
       // TODO(johnniwinther): Provide access to the import tags from which
       // the elements came.
       importScope[element.name] = new AmbiguousElementX(