Use Mac M1s or x86 wherever possible. (#49540)

Arch type was fixed to x86 because release candidate branches didn't have rosetta installed. Rosetta was enabled on December unblocking the use of M1 machines in most of mac ios sub-builds.

Bug: flutter/flutter#133207

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

Author: godofredoc

ci/builders/mac_ios_engine.json

@@ -26,8 +26,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -50,8 +49,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -74,8 +72,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -99,8 +96,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -148,8 +144,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -173,8 +168,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -198,8 +192,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",
@@ -224,8 +217,7 @@
         {
             "drone_dimensions": [
                 "device_type=none",
-                "os=Mac-12|Mac-13",
-                "cpu=x86"
+                "os=Mac-12|Mac-13"
             ],
             "gn": [
                 "--ios",