Re-enable performance_browser_tests on win8

testing/buildbot/chromium.perf.json

 {
   "Android Galaxy S5 Perf (1)": {
     "scripts": [
       {
         "name": "host_info",
         "script": "host_info.py"
       }
     ]
   },
   "Android Galaxy S5 Perf (2)": {
@@ skipping 430 matching lines @@
         ],
         "name": "load_library_perf_tests",
         "script": "gtest_perf_test.py"
       }
     ]
   },
   "Win 8 Perf (2)": {
     "scripts": [
       {
         "args": [
+          "performance_browser_tests",
+          "--test-launcher-print-test-stdio=always",
+          "--gtest_filter=TabCapturePerformanceTest.*:CastV2PerformanceTest.*",
+          "--test-launcher-jobs=1",
+          "--enable-gpu"
+        ],
+        "name": "performance_browser_tests",
+        "script": "gtest_perf_test.py"
+      },
+      {
+        "args": [
           "load_library_perf_tests",
           "--test-launcher-print-test-stdio=always"
         ],
         "name": "load_library_perf_tests",
         "script": "gtest_perf_test.py"
       }
     ]
   }
 }