`StringTokenImpl`: optimize `lexeme` resolution.

Closes https://github.com/dart-lang/sdk/pull/56453

GitOrigin-RevId: a8c4bb7114a93d15701aba22e5a16ed857df6199
Change-Id: I98aca99d59fefbd6e6a547114773ba274faa0615
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/380049
Reviewed-by: Jens Johansen <jensj@google.com>
Commit-Queue: Kevin Moore <kevmoo@google.com>
Reviewed-by: Brian Wilkerson <brianwilkerson@google.com>

https://dart.googlesource.com/sdk/+/ba041fd6b55badf1b377d8a44a0ffaa1613ebf94

DEPS

diff --git a/DEPS b/DEPS
index e834c05..8d9166e 100644
--- a/DEPS
+++ b/DEPS
@@ -282,7 +282,7 @@
 
   'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + '328c4df8329fb3ad40df54e64f5e7a9f18df4e45',
 
-  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + '89ebe93a63406ea944f16e83db42c3d555e3fb42',
+  'engine/src/flutter/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'ba041fd6b55badf1b377d8a44a0ffaa1613ebf94',
 
   'flutter': Var('flutter_git') + '/mirrors/flutter' + '@' + '593729165d14f282e51bec381939c4b017bc43f4',
 

commits.json

diff --git a/commits.json b/commits.json
index 3395d5c..d3fe53d 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
   "engine/src/flutter":"328c4df8329fb3ad40df54e64f5e7a9f18df4e45",
-  "engine/src/flutter/third_party/dart":"89ebe93a63406ea944f16e83db42c3d555e3fb42",
+  "engine/src/flutter/third_party/dart":"ba041fd6b55badf1b377d8a44a0ffaa1613ebf94",
   "flutter":"593729165d14f282e51bec381939c4b017bc43f4"
 }
\ No newline at end of file