Add tests for only-main behavior

+ move computeTransitiveDependencies to a shared location

Change-Id: I9bfad3d1799df2be36f28fac1a6ea9a8b4c4b023
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/102225
Reviewed-by: Johnni Winther <johnniwinther@google.com>

https://dart.googlesource.com/sdk/+/84fd1254ecd8e22295ced7ce915b64cb3753ec81
diff --git a/commits.json b/commits.json
index bbde73d..8a5cf77 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "external/github.com/flutter/engine":"3d2e9b24aa712ba60206e7ac392a709df0939635",
   "external/github.com/flutter/flutter":"d0c603d0bbf8898038f620fe47c3552ece07fd65",
-  "sdk":"dc31c4631c499647f0855cd5d1c84aeaf501781b"
+  "sdk":"84fd1254ecd8e22295ced7ce915b64cb3753ec81"
 }
\ No newline at end of file