correct the variable name in main.cpp
correct the variable name in main.cpp

miloyip/nativejson-benchmark,DavadDi/nativejson-benchmark,miloyip/nativejson-benchmark,DavadDi/nativejson-benchmark,DavadDi/nativejson-benchmark,miloyip/nativejson-benchmark,miloyip/nativejson-benchmark,miloyip/nativejson-benchmark,DavadDi/nativejson-benchmark,DavadDi/nativejson-benchmark