Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/a9a3ecc..bc47a86

Rolling v8/tools/clang: https://chromium.googlesource.com/chromium/src/tools/clang/+log/7ee072e..7789751

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

Change-Id: Ibdb327d012a1551f1c0a4da95b3d4e1cf772da13
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1650278Reviewed-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@{#62068}

DEPS

@@ -57,7 +57,7 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'a9a3eccc8c4093ec19a00eb8acf039378a55342f',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'bc47a860b35084241679040f74823885b0ef6fdd',
   'v8/third_party/depot_tools':
     Var('chromium_url') + '/chromium/tools/depot_tools.git' + '@' + 'e30736fb090c7f3cd82efee1fa20f7af11dda5b3',
   'v8/third_party/icu':
@@ -206,7 +206,7 @@ deps = {
       'dep_type': 'cipd',
   },
   'v8/tools/clang':
-    Var('chromium_url') + '/chromium/src/tools/clang.git' + '@' + '7ee072e439c601156b49ad0a12dcfbfb045c41e2',
+    Var('chromium_url') + '/chromium/src/tools/clang.git' + '@' + '7789751471f5a57f4b22ab088556cc1f11958c25',
   'v8/tools/luci-go': {
       'packages': [
         {