Re-enable blink_perf.canvas on Windows

Did 50 runs locally to confirm that this is working.

BUG=455796
CQ_EXTRA_TRYBOTS=tryserver.chromium.perf:linux_perf_bisect;tryserver.chromium.perf:mac_perf_bisect;tryserver.chromium.perf:win_perf_bisect;tryserver.chromium.perf:android_nexus5_perf_bisect
NOTRY=true

Review URL: https://codereview.chromium.org/1129203004

Cr-Commit-Position: refs/heads/master@{#330097}

tools/perf/benchmarks/blink_perf.py

@@ -167,7 +167,6 @@ class BlinkPerfCSS(benchmark.Benchmark):
     return CreatePageSetFromPath(path, SKIPPED_FILE)
 
 
-@benchmark.Disabled('win')  # crbug.com/455796
 class BlinkPerfCanvas(benchmark.Benchmark):
   tag = 'canvas'
   test = _BlinkPerfMeasurement