Rename a misnamed study in a field trial testing config

While field trial testing configs' _experiment_ names don't matter, I
just learned it's necessary that their _study_ names match their
server-side configurations. This change renames the
ReducedReferrerGranularity field trial testing config entry to
LimitReferrerGranularity in order to meet this requirement.

Change-Id: I2403ebc3b20919639b875553d588209e46ed6b41
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2036663Reviewed-by: Brian White <bcwhite@chromium.org>
Commit-Queue: David Van Cleve <davidvc@chromium.org>
Cr-Commit-Position: refs/heads/master@{#749740}

testing/variations/fieldtrial_testing_config.json

@@ -2930,6 +2930,26 @@
             ]
         }
     ],
+    "LimitReferrerGranularity": [
+        {
+            "platforms": [
+                "android",
+                "android_webview",
+                "chromeos",
+                "linux",
+                "mac",
+                "windows"
+            ],
+            "experiments": [
+                {
+                    "name": "Enabled",
+                    "enable_features": [
+                        "ReducedReferrerGranularity"
+                    ]
+                }
+            ]
+        }
+    ],
     "LoadingPredictorDisregardAlwaysAccessesNetwork": [
         {
             "platforms": [
@@ -4313,26 +4333,6 @@
             ]
         }
     ],
-    "ReducedReferrerGranularity": [
-        {
-            "platforms": [
-                "android",
-                "android_webview",
-                "chromeos",
-                "linux",
-                "mac",
-                "windows"
-            ],
-            "experiments": [
-                {
-                    "name": "Enabled",
-                    "enable_features": [
-                        "ReducedReferrerGranularity"
-                    ]
-                }
-            ]
-        }
-    ],
     "RendererSchedulerWakeUpThrottling": [
         {
             "platforms": [