Roll src/third_party/dart 42dcdf903c..90ff37e011 (7 commits)

dart-lang/sdk@90ff37e011 Plumb the configuration's experiments flags through to tools.
dart-lang/sdk@a7d95d4755 [dart2js] Defer ground type recipes until assembly
dart-lang/sdk@5f198ae1c8 [vm/benchmarks] Add IsolateSpawn spawn latency and memory benchmarks.
dart-lang/sdk@a9e1e7e4fd Remove 'new' from frontend_server
dart-lang/sdk@b3df8aaa12 Change subtype checking with variance for assignments and methods.
dart-lang/sdk@46cef9bfdd [vm/compiler] Drop redundant initializing stores of null
dart-lang/sdk@c54750fd8e [sdk] add a gn file for the JS dart:_interceptors library

DEPS

@@ -34,7 +34,7 @@ vars = {
   # Dart is: https://github.com/dart-lang/sdk/blob/master/DEPS.
   # You can use //tools/dart/create_updated_flutter_deps.py to produce
   # updated revision list of existing dependencies.
-  'dart_revision': '42dcdf903c97addd723f5e8332c86393934b71b0',
+  'dart_revision': '90ff37e0115c301cb742f894f64f4e3c78879df7',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py

ci/licenses_golden/licenses_third_party

-Signature: bc4d21a786e83b7d5bc617aeb8754294
+Signature: 64fa7bfa91ac6fd6be65ff8db06c8b9b
 
 UNUSED LICENSES:
 
@@ -7368,6 +7368,7 @@ FILE: ../../../third_party/dart/.mailmap
 FILE: ../../../third_party/dart/.style.yapf
 FILE: ../../../third_party/dart/.vpython
 FILE: ../../../third_party/dart/PATENT_GRANT
+FILE: ../../../third_party/dart/benchmarks/IsolateSpawn/dart/helloworld.dart
 FILE: ../../../third_party/dart/client/idea/.idea/.name
 FILE: ../../../third_party/dart/client/idea/.idea/inspectionProfiles/Project_Default.xml
 FILE: ../../../third_party/dart/client/idea/.idea/vcs.xml
@@ -7452,6 +7453,7 @@ FILE: ../../../third_party/dart/benchmarks/FfiCall/dart/native/native_functions.
 FILE: ../../../third_party/dart/benchmarks/FfiMemory/dart/FfiMemory.dart
 FILE: ../../../third_party/dart/benchmarks/FfiStruct/dart/FfiStruct.dart
 FILE: ../../../third_party/dart/benchmarks/Isolate/dart/Isolate.dart
+FILE: ../../../third_party/dart/benchmarks/IsolateSpawn/dart/IsolateSpawn.dart
 FILE: ../../../third_party/dart/runtime/bin/abi_version.h
 FILE: ../../../third_party/dart/runtime/bin/abi_version_in.cc
 FILE: ../../../third_party/dart/runtime/bin/elf_loader.cc