Remove support for 'packageRoots' in DAS.

Bug: https://github.com/dart-lang/sdk/issues/41197
Change-Id: I61929a5853b4e353e3a758fe5088f2ff2c1fda2d
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/149100
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>
Commit-Queue: Konstantin Shcheglov <scheglov@google.com>

https://dart.googlesource.com/sdk/+/a56368926e9b2525c825db6f6e4dae288f9316fb
diff --git a/commits.json b/commits.json
index 6ae0114..58a3143 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "external/github.com/flutter/engine":"c5d012900f7db0dc5dc9afb46f76d16b87915db0",
   "external/github.com/flutter/flutter":"e853155c7e36264514970dd6b67eb110fd394f78",
-  "sdk":"285767744ea3d4cda780d720f70d914768015b2c"
+  "sdk":"a56368926e9b2525c825db6f6e4dae288f9316fb"
 }
\ No newline at end of file