Update V8 DEPS.

Rolling v8/build: https://chromium.googlesource.com/chromium/src/build/+log/ec59932..5d0c607

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

Change-Id: I7bcebf5758a5993e3612c779a80f515030e54971
Reviewed-on: https://chromium-review.googlesource.com/877564Reviewed-by: v8 autoroll <v8-autoroll@chromium.org>
Commit-Queue: v8 autoroll <v8-autoroll@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50738}

DEPS

@@ -10,7 +10,7 @@ vars = {
 
 deps = {
   'v8/build':
-    Var('chromium_url') + '/chromium/src/build.git' + '@' + 'ec59932c67c4da195c8d43432b9e90f1877c7322',
+    Var('chromium_url') + '/chromium/src/build.git' + '@' + '5d0c60725f0aa5ef0b098e6b7252da83c026fec0',
   'v8/tools/gyp':
     Var('chromium_url') + '/external/gyp.git' + '@' + 'd61a9397e668fa9843c4aa7da9e79460fe590bfb',
   'v8/third_party/icu':