[gold] Always provide host ABI to gold config (#143621)

This can help us split goldens that are different due to arm non-arm mac, et cetera.

Part of https://github.com/flutter/flutter/issues/143616

packages/flutter_goldens/lib/skia_client.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'dart:convert';
+import 'dart:ffi' show Abi;
 import 'dart:io' as io;
 
 import 'package:crypto/crypto.dart';
@@ -49,8 +50,10 @@ class SkiaGoldClient {
     this.fs = const LocalFileSystem(),
     this.process = const LocalProcessManager(),
     this.platform = const LocalPlatform(),
+    Abi? abi,
     io.HttpClient? httpClient,
-  }) : httpClient = httpClient ?? io.HttpClient();
+  }) : httpClient = httpClient ?? io.HttpClient(),
+       abi = abi ?? Abi.current();
 
   /// The file system to use for storing the local clone of the repository.
   ///
@@ -74,6 +77,11 @@ class SkiaGoldClient {
   /// A client for making Http requests to the Flutter Gold dashboard.
   final io.HttpClient httpClient;
 
+  /// The ABI of the current host platform.
+  ///
+  /// If not overriden for testing, defaults to [Abi.current];
+  final Abi abi;
+
   /// The local [Directory] within the [comparisonRoot] for the current test
   /// context. In this directory, the client will create image and JSON files
   /// for the goldctl tool to use.
@@ -489,6 +497,7 @@ class SkiaGoldClient {
   String _getKeysJSON() {
     final Map<String, dynamic> keys = <String, dynamic>{
       'Platform' : platform.operatingSystem,
+      'Abi': abi.toString(),
       'CI' : 'luci',
       if (_isImpeller)
         'impeller': 'swiftshader',
@@ -567,6 +576,7 @@ class SkiaGoldClient {
         'WebRenderer' : 'canvaskit',
       'CI' : 'luci',
       'Platform' : platform.operatingSystem,
+      'Abi': abi.toString(),
       'name' : testName,
       'source_type' : 'flutter',
       if (_isImpeller)

packages/flutter_goldens/test/flutter_goldens_test.dart

@@ -5,6 +5,7 @@
 // See also dev/automated_tests/flutter_test/flutter_gold_test.dart
 
 import 'dart:convert';
+import 'dart:ffi' show Abi;
 import 'dart:io' hide Directory;
 
 import 'package:file/file.dart';
@@ -431,12 +432,13 @@ void main() {
         process: process,
         platform: platform,
         httpClient: fakeHttpClient,
+        abi: Abi.linuxX64,
       );
 
       traceID = skiaClient.getTraceID('flutter.golden.1');
       expect(
         traceID,
-        equals('ae18c7a6aa48e0685525dfe8fdf79003'),
+        equals('1937c1c93610cc0122a86a83d5bd38a4'),
       );
 
       // Browser
@@ -458,12 +460,13 @@ void main() {
         process: process,
         platform: platform,
         httpClient: fakeHttpClient,
+        abi: Abi.linuxX64,
       );
 
       traceID = skiaClient.getTraceID('flutter.golden.1');
       expect(
         traceID,
-        equals('e9d5c296c48e7126808520e9cc191243'),
+        equals('bc44a50c01eb3bbaf72a80d76c1c2305'),
       );
 
       // Locally - should defer to luci traceID
@@ -480,12 +483,13 @@ void main() {
         process: process,
         platform: platform,
         httpClient: fakeHttpClient,
+        abi: Abi.linuxX64,
       );
 
       traceID = skiaClient.getTraceID('flutter.golden.1');
       expect(
         traceID,
-        equals('9968695b9ae78cdb77cbb2be621ca2d6'),
+        equals('8821f4896801fcdd7cd6d30f5a8e4284'),
       );
     });