Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/ca471fc..4070870

TBR=machenbach@chromium.org,tmrts@chromium.org,v8-waterfall-sheriff@grotations.appspotmail.com

Change-Id: I368aa130c3f09f957cfab72c613e4e78a6e424be
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2420950Reviewed-by: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: v8-ci-autoroll-builder <v8-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Cr-Commit-Position: refs/heads/master@{#70017}

DEPS

@@ -82,7 +82,7 @@ vars = {
 
 deps = {
   'build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'ca471fc8243b09c6ed04ff339e0ac59ffd5db595',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '407087083e399b1ca56d47bcc24f1f068211e6ed',
   'third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + '244d77022cb2b0540668f2383d056b78ffcd4ca1',
   'third_party/icu':