Roll Dart forward to 8dc35ba47ee5f43e0f6ed8d9b6a3914a2c4d9577 (#2815)

- [x] Fixes devfs opening too many files.
- [x] Build fixes related to Fuschia support

DEPS

@@ -25,7 +25,7 @@ vars = {
 
   # Note: When updating the Dart revision, ensure that all entries that are
   # dependencies of dart are also updated
-  'dart_revision': 'b6e17330ed65c616a64831dbfa1027e5eaef47d6',
+  'dart_revision': '8dc35ba47ee5f43e0f6ed8d9b6a3914a2c4d9577',
   'dart_boringssl_revision': 'daeafc22c66ad48f6b32fc8d3362eb9ba31b774e',
   'dart_observatory_packages_revision': 'e5e1e543bea10d4bed95b22ad3e7aa2b20a23584',
   'dart_root_certificates_revision': 'aed07942ce98507d2be28cbd29e879525410c7fc',