Add test configs for instanced rendering

tools/flags/SkCommonFlagsConfig.h

Index: tools/flags/SkCommonFlagsConfig.h
diff --git a/tools/flags/SkCommonFlagsConfig.h b/tools/flags/SkCommonFlagsConfig.h
index dc38977cb886129227d6b26bcdcba38e82f6a3e1..641c68b3eeafe15d4c97ab8f696f58fccd685d22 100644
--- a/tools/flags/SkCommonFlagsConfig.h
+++ b/tools/flags/SkCommonFlagsConfig.h
@@ -52,11 +52,12 @@ class SkCommandLineConfigGpu : public SkCommandLineConfig {
   public:
     typedef sk_gpu_test::GrContextFactory::ContextType ContextType;
     SkCommandLineConfigGpu(const SkString& tag, const SkTArray<SkString>& viaParts,
-                           ContextType contextType, bool useNVPR, bool useDIText, int samples,
-                           SkColorType colorType, sk_sp<SkColorSpace> colorSpace);
+                           ContextType contextType, bool useNVPR, bool useInstanced, bool useDIText,
+                           int samples, SkColorType colorType, sk_sp<SkColorSpace> colorSpace);
     const SkCommandLineConfigGpu* asConfigGpu() const override { return this; }
     ContextType getContextType() const { return fContextType; }
     bool getUseNVPR() const { return fUseNVPR; }
+    bool getUseInstanced() const { return fUseInstanced; }
     bool getUseDIText() const { return fUseDIText; }
     int getSamples() const { return fSamples; }
     SkColorType getColorType() const { return fColorType; }
@@ -65,6 +66,7 @@ class SkCommandLineConfigGpu : public SkCommandLineConfig {
   private:
     ContextType fContextType;
     bool fUseNVPR;
+    bool fUseInstanced;
     bool fUseDIText;
     int fSamples;
     SkColorType fColorType;