Change FLAGS_analyticAA's default to true

BUG=skia:

Change-Id: I1abf2284ed9dfaa69110c4fe86325c8e4ee43317
Reviewed-on: https://skia-review.googlesource.com/5767
Reviewed-by: Derek Sollenberger <djsollen@google.com>
Commit-Queue: Yuqian Li <liyuqian@google.com>
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index 9e641b9..f1c08d7 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -1195,9 +1195,7 @@
         start_keepalive();
     }
 
-    if (FLAGS_analyticAA) {
-        gSkUseAnalyticAA = true;
-    }
+    gSkUseAnalyticAA = FLAGS_analyticAA;
 
     int runs = 0;
     BenchmarkStream benchStream;