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/FontCacheBench.cpp b/bench/FontCacheBench.cpp
index 35bb329..b9944f6 100644
--- a/bench/FontCacheBench.cpp
+++ b/bench/FontCacheBench.cpp
@@ -32,7 +32,7 @@
         return "fontcache";
     }
 
-    void onDraw(const int loops, SkCanvas* canvas) override {
+    void onDraw(int loops, SkCanvas* canvas) override {
         SkPaint paint;
         this->setupPaint(&paint);
         paint.setTextEncoding(SkPaint::kGlyphID_TextEncoding);
@@ -108,7 +108,7 @@
         return "fontefficiency";
     }
 
-    void onDraw(const int loops, SkCanvas* canvas) override {
+    void onDraw(int loops, SkCanvas* canvas) override {
         static bool gDone;
         if (gDone) {
             return;