Fix and triage more tests

pkg/analyzer/lib/src/fasta/ast_builder.dart

Index: pkg/analyzer/lib/src/fasta/ast_builder.dart
diff --git a/pkg/analyzer/lib/src/fasta/ast_builder.dart b/pkg/analyzer/lib/src/fasta/ast_builder.dart
index 8396f26ca1f006fdb6d0a3b7f023c1b172f09a74..6f05ef5b997073ad844f832771c6e49933aa0e27 100644
--- a/pkg/analyzer/lib/src/fasta/ast_builder.dart
+++ b/pkg/analyzer/lib/src/fasta/ast_builder.dart
@@ -1081,7 +1081,8 @@ class AstBuilder extends ScopeListener {
         return token;
       }
     }
-    return super.handleUnrecoverableError(token, message);
+    // TODO(brianwilkerson) After we've mapped all of the Fasta messages to
+    // analyzer messages, throw an error when we get to this point.

[danrubel, 2017/08/31 21:16:54]

I prefer either throwing an error message or adding a generic "not translated"
ParserErrorCode. A todo can get lost.

... but this is ok if you prefer

[Brian Wilkerson, 2017/09/01 00:48:17]

Ok, I've updated it to throw an exception, but I add a flag that can disable
this for testing purposes. If there's no throw then we get a specific list of
the errors that were expected / found, whereas a throw prevents us from
comparing the errors.

   }
 
   void handleUnaryPrefixExpression(Token token) {
@@ -1956,7 +1957,8 @@ class AstBuilder extends ScopeListener {
       default:
       // fall through
     }
-    library.addCompileTimeError(message, charOffset, uri);
+    // TODO(brianwilkerson) After we've mapped all of the Fasta messages to
+    // analyzer messages, throw an error when we get to this point.

[danrubel, 2017/08/31 21:16:54]

Ditto.

   }
 
   /// A marker method used to mark locations where a token is being located in