Roll Dart to version 7340a569caac6431d8698dc3788579b57ffcf0c6 (#9374)

* Roll Dart to version 7340a569caac6431d8698dc3788579b57ffcf0c6

Includes cherry picks to fix the following issues
- missing DT_NULL in dynamic segment" during linking
- https://github.com/flutter/flutter/issues/34308

* Update licenses file.

DEPS

@@ -32,7 +32,7 @@ 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': '1d8b81283c1dee38f1dd87b71b16aa1648b01155',
+  'dart_revision': '7340a569caac6431d8698dc3788579b57ffcf0c6',
 
   # 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: 249b5d598312923f9f21198204ef2e4f
+Signature: 9d87240ddbe083ba518018d299ee47c7
 
 UNUSED LICENSES: