Update builders to Xcode 13 and macOS 12 (flutter/engine#31915)

engine/src/flutter/.ci.yaml

@@ -58,9 +58,11 @@ platform_properties:
       caches: >-
         [
           {"name":"flutter_cocoapods","path":"cocoapods"},
-          {"name":"old_osx_sdk","path":"osx_sdk"},
+          {"name":"osx_sdk_13a233_13_15","path":"osx_sdk"},
           {"name":"builder_mac_engine","path":"builder"},
-          {"name":"openjdk","path":"java"}
+          {"name":"openjdk","path":"java"},
+          {"name":"xcode_runtime_ios-13-0","path":"xcode_runtime_ios-13-0"},
+          {"name":"xcode_runtime_ios-15-0","path":"xcode_runtime_ios-15-0"}
         ]
       # CIPD flutter_internal/java/openjdk/$platform
       dependencies: >-
@@ -69,8 +71,13 @@ platform_properties:
         ]
       device_type: none
       mac_model: "Macmini8,1"
-      os: Mac-10.15
-      xcode: 12c33 # xcode 12.3
+      os: Mac-12
+      runtime_versions: >-
+        [
+          "ios-13-0",
+          "ios-15-0"
+        ]
+      xcode: 13a233 # xcode 13.0
   windows:
     properties:
       build_host: "false"
@@ -221,6 +228,7 @@ targets:
     timeout: 60
     runIf:
       - DEPS
+      - .ci.yaml
       - lib/web_ui/**
       - web_sdk/**
       - tools/**
@@ -246,6 +254,7 @@ targets:
     timeout: 60
     runIf:
       - DEPS
+      - .ci.yaml
       - lib/web_ui/**
       - web_sdk/**
       - tools/**
@@ -296,13 +305,26 @@ targets:
     properties:
       add_recipes_cq: "true"
       gcs_goldens_bucket: flutter_logs
+      caches: >-
+        [
+          {"name":"flutter_cocoapods","path":"cocoapods"},
+          {"name":"old_osx_sdk","path":"osx_sdk"},
+          {"name":"builder_mac_engine","path":"builder"},
+          {"name":"openjdk","path":"java"}
+        ]
       dependencies: >-
         [
           {"dependency": "goldctl"}
         ]
+      os: Mac-10.15
+      runtime_versions: >-
+        [
+        ]
+      xcode: 12c33 # xcode 12.3
     timeout: 60
     runIf:
       - DEPS
+      - .ci.yaml
       - lib/web_ui/**
       - web_sdk/**
       - tools/**
@@ -387,6 +409,7 @@ targets:
     timeout: 60
     runIf:
       - DEPS
+      - .ci.yaml
       - lib/web_ui/**
       - web_sdk/**