Remove const from `const int loops`.

This drives me nuts, and prevents `while (loops --> 0)`.

BUG=skia:

Review URL: https://codereview.chromium.org/1379923005
diff --git a/bench/GameBench.cpp b/bench/GameBench.cpp
index b1edf2e..823f5b0 100644
--- a/bench/GameBench.cpp
+++ b/bench/GameBench.cpp
@@ -86,7 +86,7 @@
         }
     }
 
-    void onDraw(const int loops, SkCanvas* canvas) override {
+    void onDraw(int loops, SkCanvas* canvas) override {
         SkRandom scaleRand;
         SkRandom transRand;
         SkRandom rotRand;