Do not autoroll gradle and roll gradle back to 3.5.0.

We want to use stable gradle releases for testing.

BUG=webrtc:7608
NOTRY=True

Review-Url: https://codereview.webrtc.org/2877723002
Cr-Commit-Position: refs/heads/master@{#18094}
diff --git a/DEPS b/DEPS
index 38a2959..db0aeef 100644
--- a/DEPS
+++ b/DEPS
@@ -118,7 +118,7 @@
     # Gradle 3.5.0. Used for testing Android Studio project generation for WebRTC.
     'src/webrtc/examples/androidtests/third_party/gradle':
       Var('chromium_git') + '/external/github.com/gradle/gradle.git' + '@' +
-      'f0033cd6fdde56471115e18b15261b92f0ec0629',
+      'b762622a185d59ce0cfc9cbc6ab5dd22469e18a6',
   },
   'ios': {
     'src/ios':