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/StrokeBench.cpp b/bench/StrokeBench.cpp
index d673748..63199d0 100644
--- a/bench/StrokeBench.cpp
+++ b/bench/StrokeBench.cpp
@@ -27,7 +27,7 @@
 
     const char* onGetName() override { return fName.c_str(); }
 
-    void onDraw(const int loops, SkCanvas* canvas) override {
+    void onDraw(int loops, SkCanvas* canvas) override {
         SkPaint paint(fPaint);
         this->setupPaint(&paint);