Port parser and scanner fixes from rasta branch.

pkg/front_end/lib/src/fasta/scanner/keyword.dart

Index: pkg/front_end/lib/src/fasta/scanner/keyword.dart
diff --git a/pkg/front_end/lib/src/fasta/scanner/keyword.dart b/pkg/front_end/lib/src/fasta/scanner/keyword.dart
index 2038c6b40a950b3d0bd139badce745a0292edaff..1b06fb9b2d0c97df17186c679f762f4ccf41347a 100644
--- a/pkg/front_end/lib/src/fasta/scanner/keyword.dart
+++ b/pkg/front_end/lib/src/fasta/scanner/keyword.dart
@@ -74,16 +74,17 @@ class Keyword {
     const Keyword("static", isBuiltIn: true),
     const Keyword("typedef", isBuiltIn: true),
 
+    const Keyword("async", isPseudo: true),
+    const Keyword("await", isPseudo: true),
+    const Keyword("deferred", isPseudo: true),
     const Keyword("hide", isPseudo: true),
     const Keyword("native", isPseudo: true),
     const Keyword("of", isPseudo: true),
     const Keyword("on", isPseudo: true),
+    const Keyword("patch", isPseudo: true),
     const Keyword("show", isPseudo: true),
     const Keyword("source", isPseudo: true),
-    const Keyword("deferred", isPseudo: true),
-    const Keyword("async", isPseudo: true),
     const Keyword("sync", isPseudo: true),
-    const Keyword("await", isPseudo: true),
     const Keyword("yield", isPseudo: true),
   ];