remove fasta <--> analyzer token translation

pkg/front_end/test/scanner_fasta_test.dart

Index: pkg/front_end/test/scanner_fasta_test.dart
diff --git a/pkg/front_end/test/scanner_fasta_test.dart b/pkg/front_end/test/scanner_fasta_test.dart
index 9404a293ef8fdd24a9dbc46fc056dfc4a7871469..e6dd4bd4298ff3653e41f463bae01f94490f4b59 100644
--- a/pkg/front_end/test/scanner_fasta_test.dart
+++ b/pkg/front_end/test/scanner_fasta_test.dart
@@ -18,7 +18,6 @@ main() {
   defineReflectiveSuite(() {
     defineReflectiveTests(ScannerTest_Fasta);
     defineReflectiveTests(ScannerTest_Fasta_Direct);
-    defineReflectiveTests(ScannerTest_Fasta_Roundtrip);
   });
 }
 
@@ -507,21 +506,6 @@ class ScannerTest_Fasta_Direct extends ScannerTest_Fasta_Base {
   }
 }
 
-/// Scanner tests that exercise the Fasta scanner, then convert the tokens to
-/// analyzer tokens, then convert back to Fasta tokens before checking
-/// assertions.
-@reflectiveTest
-class ScannerTest_Fasta_Roundtrip extends ScannerTest_Fasta_Base {
-  @override
-  Token scan(String source) {
-    var scanner = new fasta.StringScanner(source, includeComments: true);
-    var fastaTokenStream = scanner.tokenize();
-    var analyzerTokenStream = new ToAnalyzerTokenStreamConverter_NoErrors()
-        .convertTokens(fastaTokenStream);
-    return fromAnalyzerTokenStream(analyzerTokenStream);
-  }
-}
-
 /// Override of [ToAnalyzerTokenStreamConverter] that verifies that there are no
 /// errors.
 class ToAnalyzerTokenStreamConverter_NoErrors