Use AOT snapshot of kernel_worker

Author: a-siva

test_common/lib/sdk_asset_generator.dart

@@ -212,7 +212,7 @@ class SdkAssetGenerator {
       ];
 
       _logger.fine('Executing dart ${args.join(' ')}');
-      final process = await Process.start(sdkLayout.dartPath, args,
+      final process = await Process.start(sdkLayout.dartAotRuntimePath, args,
           workingDirectory: sdkLayout.sdkDirectory);
 
       final output = <String>[];

test_common/lib/test_sdk_layout.dart

@@ -108,7 +108,7 @@ class TestSdkLayout {
           sdkLayout.sdkDirectory,
           'bin',
           'snapshots',
-          'kernel_worker.dart.snapshot',
+          'kernel_worker_aot.dart.snapshot',
         ),
         devToolsDirectory: p.join(
           sdkLayout.sdkDirectory,