Revert "Add ThrottleDelayable 4G params to fieldtrial_testing_config.json"

This reverts commit 69c98ffc.

Reason for revert: The field trial experiment was turned down since
it did not show any improvement (see http://shortn/_3N4YH2mKyq). Besides, the perf bots showed a
regression.

Original change's description:
> Add ThrottleDelayable 4G params to fieldtrial_testing_config.json
> 
> Bug: 746640
> Change-Id: Ie312a7756f5e6917a4d7c2bd107951f4928e97d0
> Reviewed-on: https://chromium-review.googlesource.com/1024054
> Reviewed-by: Jesse Doherty <jwd@chromium.org>
> Commit-Queue: Tarun Bansal <tbansal@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#552765}

TBR=jwd@chromium.org,tbansal@chromium.org

# Not skipping CQ checks because original CL landed > 1 day ago.

Bug: 746640, 838443
Change-Id: I349ed4bdafedeadb8e80af332472937babb7b820
Reviewed-on: https://chromium-review.googlesource.com/1117220Reviewed-by: Tarun Bansal <tbansal@chromium.org>
Reviewed-by: Alexei Svitkine <asvitkine@chromium.org>
Commit-Queue: Tarun Bansal <tbansal@chromium.org>
Cr-Commit-Position: refs/heads/master@{#570875}

testing/variations/fieldtrial_testing_config.json

@@ -4029,11 +4029,8 @@
                     "name": "Enabled",
                     "params": {
                         "EffectiveConnectionType1": "3G",
-                        "EffectiveConnectionType2": "4G",
                         "MaxDelayableRequests1": "14",
-                        "MaxDelayableRequests2": "18",
-                        "NonDelayableWeight1": "3.0",
-                        "NonDelayableWeight2": "3.0"
+                        "NonDelayableWeight1": "2.0"
                     },
                     "enable_features": [
                         "ThrottleDelayable"