Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/afc55ca..49ce9a3

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

Change-Id: I70102bf08d91bdc1503e1dd8160dbee9b252bf7a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2553924Reviewed-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@{#71328}

DEPS

@@ -88,7 +88,7 @@ vars = {
 
 deps = {
   'build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'afc55ca8f3f12edb363e5cf52eb1f506cfc9a716',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '49ce9a35fc22efe144eb5bdad9233578eb69e003',
   'third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + '9c0dc3026eedcd500b61df4f5a36febc1edda545',
   'third_party/icu':