Update DevTools DEPS (trusted)

Rolling buildtools: https://chromium.googlesource.com/chromium/src/buildtools/+log/015ef44..be957e3

Roll created at https://cr-buildbucket.appspot.com/build/8717252078736908305

Bug: none
Change-Id: Ic4a34a542c0dccf2415d420246f3376c9c3ea6fa
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/6468676
Bot-Commit: Devtools Autoroller <devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>
Commit-Queue: Devtools Autoroller <devtools-ci-autoroll-builder@chops-service-accounts.iam.gserviceaccount.com>

Author: devtools-ci-autoroll-builder

DEPS

@@ -15,7 +15,7 @@ vars = {
   'build_revision': 'e13953ced04ed05f45aa3c961bd6d802aced74ec',
 
   'buildtools_url': 'https://chromium.googlesource.com/chromium/src/buildtools.git',
-  'buildtools_revision': '015ef44748f454ec2840326efc2e72579ebe25ec',
+  'buildtools_revision': 'be957e3dcf100b5a72e90a555fe1858e3734f52a',
 
   'depot_tools_url': 'https://chromium.googlesource.com/chromium/tools/depot_tools.git',
   'depot_tools_revision': 'f40ddcd8d51626fb7be3ab3c418b3f3be801623f',