Update cross-context options encoding to account for patchPlatform.

pkg/analysis_server/lib/src/status/get_handler.dart

Index: pkg/analysis_server/lib/src/status/get_handler.dart
diff --git a/pkg/analysis_server/lib/src/status/get_handler.dart b/pkg/analysis_server/lib/src/status/get_handler.dart
index c89a26fcba1339eb2d9227a29950495aac947a3c..32ba19453bebed8742b50b7ddb60c0f6a61c2bce 100644
--- a/pkg/analysis_server/lib/src/status/get_handler.dart
+++ b/pkg/analysis_server/lib/src/status/get_handler.dart
@@ -413,7 +413,7 @@ class GetHandler {
    */
   String _encodeSdkDescriptor(SdkDescription descriptor) {
     StringBuffer buffer = new StringBuffer();
-    buffer.write(descriptor.options.encodeCrossContextOptions());
+    buffer.write(descriptor.options.encodeCrossContextOptions().join(','));
     for (String path in descriptor.paths) {
       buffer.write('+');
       buffer.write(path);