Update DevTools DEPS (trusted)

Rolling buildtools: https://chromium.googlesource.com/chromium/src/buildtools/+log/c603d82..8f7ec31

Roll created at https://cr-buildbucket.appspot.com/build/8694274424601164561

Bug: none
Change-Id: I4545cfed67e84a83db8eb6786f0c52a678b50fee
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/7347955
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': '726ac7741fe428eff5da63e0374c66f7f25788b8',
 
   'buildtools_url': 'https://chromium.googlesource.com/chromium/src/buildtools.git',
-  'buildtools_revision': 'c603d823d75e866247fb1c69094fda3dc4c34dbe',
+  'buildtools_revision': '8f7ec316d620c8b5e51679775e125c9c190ce4ce',
 
   'depot_tools_url': 'https://chromium.googlesource.com/chromium/tools/depot_tools.git',
   'depot_tools_revision': '967382fdcd1477dab3a7fec8eec3e3d5368bb0fe',