Roll src/third_party/dart 134e0e28cd..96e7a4ff30 (38 commits) (flutter/engine#14058)

dart-lang/sdk@96e7a4ff30 [dart:async] Temporarily work around compilation errors
dart-lang/sdk@10f158654e Return the URL of recently published docs
dart-lang/sdk@61f5e88454 [CFE] [Strong test] Check non-serialized expectations first
dart-lang/sdk@3e5ae6adaf Revert "[dartdevc] Break dart:_debugger dependency on dart:html"
dart-lang/sdk@f6a76586de [analyzer] send additional data to crash reporting
dart-lang/sdk@461b80a0e4 [dartdevc] Fix analysis errors in NNBD dart:core patch file
dart-lang/sdk@abeebc04e0 Compute LUB for FunctionType(s) in one pass over parameters.
dart-lang/sdk@edf08f63ed [dartfuzz] Temporarily disabling Int32x4
dart-lang/sdk@1a6b76a8a0 Update DeprecatedMemberUseTest from ResolverTestCase to DriverResolutionTest.
dart-lang/sdk@dc3af706e9 [nnbd_migration] assume non-nullability in is check
dart-lang/sdk@1ecb8c7038 [ dartfuzz ] Added update_spreadsheet.py which automatically updates DartFuzzStats with latest fuzzing run results
dart-lang/sdk@c2c716d0c5 [ Observatory ] Fix issue where timeline would hang if CPU profiling was disabled.
dart-lang/sdk@740af3c009 [dartdevc] Pass nnbd experiment to analyzer in check_nnbd_sdk.dart
dart-lang/sdk@1d914d2e7e Revert "[dartdevc] Migrating dart:_js_helper to NNBD."
dart-lang/sdk@674810a38d Generated overriding methods throw an exception rather than returning null
dart-lang/sdk@bb76f935c1 [nnbd_migration] Better descriptions for the most common bangs
dart-lang/sdk@3524bb1a93 [co19] Roll co19_2 and add co19 (nnbd) to DEPS.
dart-lang/sdk@3b99524167 Revert "[observatory] Properly wait for Catapult's iframe to load. Give message while fetching timeline."
dart-lang/sdk@a5a9057d73 [cfe] Add non-function type alias usage tests
dart-lang/sdk@b563d6cad5 [kernel] Exclude pkg/kernel from front_end spell checking
dart-lang/sdk@d5dbf10672 [SDK] Adds non-eager async stack frame collector.
dart-lang/sdk@cdb9830a54 [cfe] Shard text_serialization tests
dart-lang/sdk@ee8d9d2fd3 Remove unused getters from AnalysisResult.
dart-lang/sdk@42ec44a6a4 Reland "Revamp patch_sdk.dart mainly to use libraries.json."
dart-lang/sdk@58e9aeafdb Deprecate AnalysisSession.typeProvider and typeSystem.
dart-lang/sdk@3663abd8db Update the header in the generated diagnostic docs
dart-lang/sdk@3e86e8f8fb [dartdevc] Migrating dart:_js_helper to NNBD.
dart-lang/sdk@4987416f69 [nnbd_migration] Only restyle code links (which I also bolded)
dart-lang/sdk@273ca5858b Deprecate AnalysisContext.typeProvider/typeSystem
dart-lang/sdk@965fb9942f [dartdevc] Restore dart:core imports in dart:_internal patch file
dart-lang/sdk@0019bf646b [migration] handle side casts, assume non-null with const guard.
dart-lang/sdk@d89252d369 [nnbd_migration] make tooltips stickier
dart-lang/sdk@cdab81c21a Remove CompilationUnitElement from ElementWalker.forExecutable()
dart-lang/sdk@cc5976f78b Remove TypeProvider parameter from createLoadLibraryFunction()
dart-lang/sdk@687ef66bfd Remove InternalAnalysisContext.
dart-lang/sdk@53d3b5d780 Generate the auxiliary files in a subdirectory
dart-lang/sdk@18b7580944 [analyzer] for 'Failed to handle request' errors, send the exception to crash reporting as well
dart-lang/sdk@b19436061d [migration] enable typed data in migration -- fatal exception is gone.

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': '134e0e28cda1f8110a69bad34ae70e8123475a80',
+  'dart_revision': '96e7a4ff30c5850762225efca0fa1b48f28c1666',
 
   # WARNING: DO NOT EDIT MANUALLY
   # The lines between blank lines above and below are generated by a script. See create_updated_flutter_deps.py