Land v8-side changes to switch to v8_current_cpu in the GN build.

build_overrides/v8.gni

Index: build_overrides/v8.gni
diff --git a/build_overrides/v8.gni b/build_overrides/v8.gni
index 5dcd67257a8e40443db653b45cea8e2394efdbe3..a57f244f2ad0b1e998a2ad69229f822c73d8c577 100644
--- a/build_overrides/v8.gni
+++ b/build_overrides/v8.gni
@@ -4,18 +4,17 @@
 
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
-import("//build/config/v8_target_cpu.gni")
 import("//gni/v8.gni")
 
 if (is_android) {
   import("//build/config/android/config.gni")
 }
 
-if (((v8_target_cpu == "x86" ||
-      v8_target_cpu == "x64" ||
-      v8_target_cpu=="x87") &&
+if (((v8_current_cpu == "x86" ||
+      v8_current_cpu == "x64" ||
+      v8_current_cpu=="x87") &&
      (is_linux || is_mac)) ||
-    (v8_target_cpu == "ppc64" && is_linux)) {
+    (v8_current_cpu == "ppc64" && is_linux)) {
   v8_enable_gdbjit = true
 }