[dart2js] Add Bitset and EnumSetDomain abstractions.

Change-Id: I85b401d7eb13e0d9ba0bfcb37aebdb28e65bc77f
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/395062
Reviewed-by: Stephen Adams <sra@google.com>
Reviewed-by: Nate Biggs <natebiggs@google.com>

https://dart.googlesource.com/sdk/+/0bfa0b05a2551ab4c8262ad0ef767d73087c7770

DEPS

diff --git a/DEPS b/DEPS
index 4ce1083..6233d97 100644
--- a/DEPS
+++ b/DEPS
@@ -260,7 +260,7 @@
 
   'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '764b91d7d75af08a334a1509cd24cdefcc16f2e5',
 
-  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'ab1f7fccc60819837c588828da6db222fec7d5bb',
+  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '0bfa0b05a2551ab4c8262ad0ef767d73087c7770',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + 'd7f5547ecd036d80f408935e4dc154a0dbe0b8d8',
 

commits.json

diff --git a/commits.json b/commits.json
index 435ca56..2e6fde7 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "engine/src/flutter":"764b91d7d75af08a334a1509cd24cdefcc16f2e5",
-  "engine/src/flutter/third_party/dart":"ab1f7fccc60819837c588828da6db222fec7d5bb",
+  "engine/src/flutter/third_party/dart":"0bfa0b05a2551ab4c8262ad0ef767d73087c7770",
   "flutter":"d7f5547ecd036d80f408935e4dc154a0dbe0b8d8"
 }
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