Replace benchmarks with its v2 version. (flutter/engine#42677)

Benchmarks has been migrated to engine v2 and it is ready to replace the legacy version.

[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style

engine/src/flutter/.ci.yaml

@@ -184,6 +184,7 @@ targets:
     timeout: 60
 
   - name: Linux Benchmarks
+    bringup: true
     enabled_branches:
       - main
       - master
@@ -195,7 +196,6 @@ targets:
     timeout: 60
 
   - name: Linux linux_benchmarks
-    bringup: true
     enabled_branches:
       - main
     recipe: engine_v2/builder