Remove dead code _resolveUri in builtin.dart is not used anymore.

runtime/bin/builtin.dart

Index: runtime/bin/builtin.dart
diff --git a/runtime/bin/builtin.dart b/runtime/bin/builtin.dart
index 70451878b9e9413edc870386166abd18397bce54..7780208d68dd0da2a16f17e82e38c6848460f801 100644
--- a/runtime/bin/builtin.dart
+++ b/runtime/bin/builtin.dart
@@ -261,27 +261,6 @@ String _resolveScriptUri(String scriptName) {
   return scriptUri.toString();
 }
 
-// Embedder Entrypoint:
-// Function called by standalone embedder to resolve uris when the VM requests
-// Dart_kCanonicalizeUrl from the tag handler.
-String _resolveUri(String base, String userString) {
-  if (!_setupCompleted) {
-    _setupHooks();
-  }
-
-  if (_traceLoading) {
-    _log('Resolving: $userString from $base');
-  }
-
-  var baseUri = Uri.parse(base);
-  var result = baseUri.resolve(userString).toString();
-  if (_traceLoading) {
-    _log('Resolved $userString in $base to $result');
-  }
-
-  return result;
-}
-
 // Embedder Entrypoint (gen_snapshot):
 // Resolve relative paths relative to working directory.
 String _resolveInWorkingDirectory(String fileName) {