Roll Fuchsia SDK from 25.20241104.6.1 to 26.20241209.5.1

Cq-Include-Trybots: luci.dart.try:vm-fuchsia-release-x64-try,vm-fuchsia-release-arm64-try
Change-Id: Iee85e6c34b588601fd26b383ec6bd8adaafbcc21
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/399628
Commit-Queue: Ryan Macnak <rmacnak@google.com>
Reviewed-by: Siva Annamalai <asiva@google.com>

DEPS

@@ -85,7 +85,7 @@ vars = {
   "download_reclient": True,
 
   # Update from https://chrome-infra-packages.appspot.com/p/fuchsia/sdk/core
-  "fuchsia_sdk_version": "version:25.20241104.6.1",
+  "fuchsia_sdk_version": "version:26.20241209.5.1",
   "download_fuchsia_deps": False,
 
   # Ninja, runs the build based on files generated by GN.

pkg/test_runner/lib/src/fuchsia.dart

@@ -25,7 +25,7 @@ class FuchsiaEmulator {
     var args = <String>[
       "./build/fuchsia/test_env.py",
       "--out-dir=${_outDir(buildDir, mode)}",
-      "--device-spec=virtual_device_large",
+      "--device-spec=$arch-emu-large",
       "--packages=dart_test_$mode.far",
       "--logs-dir=${daemonIsolateDir!.path}"
     ];