Update all occurrences of raw strings.

utils/tests/pub/test_pub.dart

Index: utils/tests/pub/test_pub.dart
diff --git a/utils/tests/pub/test_pub.dart b/utils/tests/pub/test_pub.dart
index 3a64e0575f0fd88d096067a38e227dded73c0e23..c5a6b84d3ec3cda484fe1cff5f8a92d2f923b143 100644
--- a/utils/tests/pub/test_pub.dart
+++ b/utils/tests/pub/test_pub.dart
@@ -302,7 +302,7 @@ DirectoryDescriptor packageCacheDir(String name, String version) {
 DirectoryDescriptor gitPackageRevisionCacheDir(String name, [int modifier]) {
   var value = name;
   if (modifier != null) value = "$name $modifier";
-  return dir(new RegExp("$name${@'-[a-f0-9]+'}"), [
+  return dir(new RegExp("$name${r'-[a-f0-9]+'}"), [
     libDir(name, value)
   ]);
 }
@@ -312,7 +312,7 @@ DirectoryDescriptor gitPackageRevisionCacheDir(String name, [int modifier]) {
  * in the repo cache of the global package cache.
  */
 DirectoryDescriptor gitPackageRepoCacheDir(String name) {
-  return dir(new RegExp("$name${@'-[a-f0-9]+'}"), [
+  return dir(new RegExp("$name${r'-[a-f0-9]+'}"), [
     dir('branches'),
     dir('hooks'),
     dir('info'),