Add builders for arm64 on macOS unopt (#41141)

Add builders for arm64 on macOS unopt
https://dart.googlesource.com/external/github.com/flutter/engine/+/eb3e7d52ebbc4ef85a979c50aa09ec19efdb2162

DEPS

diff --git a/DEPS b/DEPS
index a1f202c..b8e2fe6 100644
--- a/DEPS
+++ b/DEPS
@@ -243,7 +243,7 @@
 deps = {
   'engine/src': 'https://github.com/flutter/buildroot.git' + '@' + '48f8487897b7f40e2744c808694535478d06ca47',
 
-  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + 'f5dab1b935c5dce2bf5770bbcf6a5311f9eea36f',
+  'engine/src/flutter': Var('flutter_git') + '/mirrors/engine' + '@' + 'eb3e7d52ebbc4ef85a979c50aa09ec19efdb2162',
 
   'engine/src/third_party/dart': Var('dart_git') + '/sdk' + '@' + 'badd96032df786c9c4e4b02a7fe6705c8a8bda78',
 

commits.json

diff --git a/commits.json b/commits.json
index 9b9e39a..bd9fb0b 100644
--- a/commits.json
+++ b/commits.json
@@ -1,5 +1,5 @@
 {
-  "engine/src/flutter":"f5dab1b935c5dce2bf5770bbcf6a5311f9eea36f",
+  "engine/src/flutter":"eb3e7d52ebbc4ef85a979c50aa09ec19efdb2162",
   "engine/src/third_party/dart":"badd96032df786c9c4e4b02a7fe6705c8a8bda78",
   "flutter":"55dc9f93ea0cb286bffc8d849049bfde96d36a99"
 }
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