Reverts "Pin local_engine mac builds to arm64 (#56172)" (#56179)

<!-- start_original_pr_link -->
Reverts: #56172
<!-- end_original_pr_link -->
<!-- start_initiating_author -->
Initiated by: jonahwilliams
<!-- end_initiating_author -->
<!-- start_revert_reason -->
Reason for reverting: mysterious infra failures:
https://ci.chromium.org/ui/p/flutter/builders/prod/Linux%20local_engine_builds/2951/overview
<!-- end_revert_reason -->
<!-- start_original_pr_author -->
Original PR Author: zanderso
<!-- end_original_pr_author -->

<!-- start_reviewers -->
Reviewed By: {chinmaygarde}
<!-- end_reviewers -->

<!-- start_revert_body -->
This change reverts the following previous change:
No description provided.
<!-- end_revert_body -->

Co-authored-by: auto-submit[bot] <flutter-engprod-team@google.com>

Author: auto-submit[bot]

ci/builders/local_engine.json

@@ -4,8 +4,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -38,8 +37,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -73,8 +71,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -107,8 +104,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -141,8 +137,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -176,8 +171,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -213,8 +207,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "use_rbe": true
@@ -325,8 +318,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "use_rbe": true
@@ -359,8 +351,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "use_rbe": true
@@ -444,8 +435,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "use_rbe": true
@@ -529,8 +519,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -562,8 +551,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -596,8 +584,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -630,8 +617,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -770,8 +756,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,
@@ -855,8 +840,7 @@
       "cas_archive": false,
       "drone_dimensions": [
         "os=Mac-13|Mac-14",
-        "device_type=none",
-        "cpu=arm64"
+        "device_type=none"
       ],
       "gclient_variables": {
         "download_android_deps": false,