Revert "Roll src/third_party/dart b5aeaa6796...966038ef58 (flutter#9708)" (flutter#9711)

This reverts commit cd2ab37.

Author: a-siva

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': '966038ef5827987d30a5091ec04c6a2a4e04d9ed',
+  'dart_revision': 'b5aeaa67960c03e528b76c5cfa55059a058de34e',
 
   # 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

@@ -1,4 +1,4 @@
-Signature: 6e345aeac70f493589c1c1ecc5f2350a
+Signature: eba9f5f513005a7e6179d4faf3731252
 
 UNUSED LICENSES:
 
@@ -4614,7 +4614,6 @@ FILE: ../../../third_party/dart/runtime/observatory/web/favicon.ico
 FILE: ../../../third_party/dart/runtime/observatory/web/index.html
 FILE: ../../../third_party/dart/runtime/observatory/web/third_party/trace_viewer_full.html
 FILE: ../../../third_party/dart/runtime/observatory/web/timeline.html
-FILE: ../../../third_party/dart/runtime/vm/compiler/ffi_dbc_trampoline_arm64.S
 FILE: ../../../third_party/dart/runtime/vm/compiler/ffi_dbc_trampoline_x64_linux_mac.S
 FILE: ../../../third_party/dart/samples/ffi/sqlite/docs/lib/scenario-default.svg
 FILE: ../../../third_party/dart/samples/ffi/sqlite/docs/lib/scenario-full.svg