Cleanup isolate library after frog removal.

lib/compiler/implementation/library_map.dart

Index: lib/compiler/implementation/library_map.dart
diff --git a/lib/compiler/implementation/library_map.dart b/lib/compiler/implementation/library_map.dart
index fad9185afe7ed781ca821ab2a106238889d9d6e3..6420535406d3dd9168f46cf7f950e2af40102d3b 100644
--- a/lib/compiler/implementation/library_map.dart
+++ b/lib/compiler/implementation/library_map.dart
@@ -43,16 +43,12 @@ final Map<String, LibraryInfo> DART2JS_LIBRARY_MAP
   "io": const LibraryInfo(
       "lib/compiler/implementation/lib/io.dart"),
   "isolate": const LibraryInfo(
-      "lib/isolate/isolate_leg.dart"),
-  "json": const LibraryInfo(
-      "lib/json/json.dart"),
+      "lib/isolate/isolate_dart2js.dart"),
+  "json": const LibraryInfo("lib/json/json.dart"),
   "math": const LibraryInfo(
       "corelib/unified/math/math.dart",
       "lib/compiler/implementation/lib/math.dartp", isInternal: true),
-  "uri": const LibraryInfo(
-      "lib/uri/uri.dart"),
-  "utf": const LibraryInfo(
-      "lib/utf/utf.dart"),
-  "web": const LibraryInfo(
-      "lib/web/web.dart"),
+  "uri": const LibraryInfo("lib/uri/uri.dart"),
+  "utf": const LibraryInfo("lib/utf/utf.dart"),
+  "web": const LibraryInfo("lib/web/web.dart"),
 };