Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/bc497ad..49d87d5

TBR=machenbach@chromium.org,tmrts@chromium.org

Change-Id: I524a369fac23f095d2c88a7dd744d4909702c849
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2068980Reviewed-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@{#66397}

DEPS

@@ -72,7 +72,7 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'bc497ad7d60769f6f98ebc5cdf0039435c6ef007',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '49d87d57f67a640eb2f0d07f2f049a4ee337ac0e',
   'v8/third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + '1773f37de61efb55634bc3966510141df5ecf143',
   'v8/third_party/icu':