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/RectoriBench.cpp b/bench/RectoriBench.cpp
index 8d8bd3d..1f4da86 100644
--- a/bench/RectoriBench.cpp
+++ b/bench/RectoriBench.cpp
@@ -25,7 +25,7 @@
         return "rectori";
     }
 
-    void onDraw(const int loops, SkCanvas* canvas) override {
+    void onDraw(int loops, SkCanvas* canvas) override {
         SkRandom Random;
 
         for (int i = 0; i < loops; i++) {