Land chromium-side work to clean up handling of v8_target_cpu in the GN build.

chrome/test/base/js2gtest.gni

Index: chrome/test/base/js2gtest.gni
diff --git a/chrome/test/base/js2gtest.gni b/chrome/test/base/js2gtest.gni
index c4fde1f4865dd02e3155c6c28264130c70037b88..50d3c8459e19bb7f549d5dda53121960c3c0c23b 100644
--- a/chrome/test/base/js2gtest.gni
+++ b/chrome/test/base/js2gtest.gni
@@ -37,7 +37,7 @@ template("js2gtest") {
 
     sources = invoker.sources
 
-    v8_shell_path = get_label_info("//v8:v8_shell($snapshot_toolchain)",
+    v8_shell_path = get_label_info("//v8:v8_shell($v8_snapshot_toolchain)",
                                    "root_out_dir") + "/v8_shell"
     if (is_win) {
       v8_shell_path += ".exe"
@@ -90,7 +90,7 @@ template("js2gtest") {
     ]
 
     deps = [
-      "//v8:v8_shell($snapshot_toolchain)",
+      "//v8:v8_shell($v8_snapshot_toolchain)",
     ]
     if (defined(invoker.deps)) {
       deps += invoker.deps