Add 'flutter_release' patch_sdk mode to patch_sdk

pkg/front_end/lib/src/fasta/compiler_command_line.dart

Index: pkg/front_end/lib/src/fasta/compiler_command_line.dart
diff --git a/pkg/front_end/lib/src/fasta/compiler_command_line.dart b/pkg/front_end/lib/src/fasta/compiler_command_line.dart
index 8fc042009bbf00c5a99962de759f5d6fc7815495..2ad1e11903adb7c07b8117bd5af1e99518a4b5a3 100644
--- a/pkg/front_end/lib/src/fasta/compiler_command_line.dart
+++ b/pkg/front_end/lib/src/fasta/compiler_command_line.dart
@@ -195,7 +195,7 @@ Supported options:
     Read the SDK platform from <file>, which should be in Dill/Kernel IR format
     and contain the Dart SDK.
 
-  --target=none|vm|vmcc|vmreify|flutter
+  --target=none|vm|vm_fasta|vmcc|vmreify|flutter|flutter_fasta|flutter_fasta_release

[ahe, 2017/07/10 13:19:02]

Perhaps we should change this to:

  --target=TARGET
    Specify the target configuration, where TARGET is one of 'none', 'vm',
    'vm_fasta', 'vmcc', 'vmreify', 'flutter', 'flutter_fasta', or
    'flutter_fasta_release'.

[aam, 2017/07/10 22:11:37]

Done.

     Specify the target configuration.
 
   --verify