Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/bd2533d..6455acf

Rolling v8/third_party/icu: https://chromium.googlesource.com/chromium/deps/icu/+log/ccad447..b029971

TBR=machenbach@chromium.org,hablich@chromium.org,sergiyb@chromium.org

Change-Id: I4eec5e59be17ef15b3e4698c6ef6852e185dfc88
Reviewed-on: https://chromium-review.googlesource.com/c/1293073Reviewed-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@{#56837}

DEPS

@@ -13,11 +13,11 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'bd2533df2c1164ee26f567bc13bbd9f9a7ec5239',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '6455acf1c78ab1f3a9be215adaa0fd7ce8017dea',
   'v8/third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + '98f1e59b41c6c580cd168ac4456bf27d78c12a95',
   'v8/third_party/icu':
-    Var('chromium_url') + '/chromium/deps/icu.git' + '@' + 'ccad4472126e35ccd1d19bea38b6675802d40472',
+    Var('chromium_url') + '/chromium/deps/icu.git' + '@' + 'b029971f1fc6b20d06887c47c7afebd5881f31ff',
   'v8/third_party/instrumented_libraries':
     Var('chromium_url') + '/chromium/src/third_party/instrumented_libraries.git' + '@' + 'a90cbf3b4216430a437991fb53ede8e048dea454',
   'v8/buildtools':