nanobench: Add some Valgrind failure paranoia.

bench/nanobench.cpp

Index: bench/nanobench.cpp
diff --git a/bench/nanobench.cpp b/bench/nanobench.cpp
index 38f554dea447103975dc01ee32fededd0f3ef1fa..b2a35df6461a213b85bb5f2142582f15db83800a 100644
--- a/bench/nanobench.cpp
+++ b/bench/nanobench.cpp
@@ -1084,6 +1084,7 @@ public:
             log->configOption("clip",
                     SkStringPrintf("%d %d %d %d", fClip.fLeft, fClip.fTop,
                                                   fClip.fRight, fClip.fBottom).c_str());
+            SK_ALWAYSBREAK(fCurrentScale < fScales.count());  // debugging paranoia
             log->configOption("scale", SkStringPrintf("%.2g", fScales[fCurrentScale]).c_str());
             if (fCurrentUseMPD > 0) {
                 SkASSERT(1 == fCurrentUseMPD || 2 == fCurrentUseMPD);