Fix a tensorflow test bug. (#3165)
Fix a tensorflow test bug. (#3165)

Length of input_shape isn't always 4.
sxjscience/tvm,tqchen/tvm,sxjscience/tvm,sxjscience/tvm,tqchen/tvm,Huyuwei/tvm,dmlc/tvm,sxjscience/tvm,Huyuwei/tvm,sxjscience/tvm,sxjscience/tvm,Laurawly/tvm-1,Laurawly/tvm-1,tqchen/tvm,Laurawly/tvm-1,Huyuwei/tvm,Huyuwei/tvm,tqchen/tvm,sxjscience/tvm,tqchen/tvm,dmlc/tvm,tqchen/tvm,Huyuwei/tvm,Laurawly/tvm-1,Laurawly/tvm-1,Huyuwei/tvm,tqchen/tvm,sxjscience/tvm,dmlc/tvm,Huyuwei/tvm,Laurawly/tvm-1,dmlc/tvm,Huyuwei/tvm,dmlc/tvm,tqchen/tvm,Huyuwei/tvm,sxjscience/tvm,dmlc/tvm,Laurawly/tvm-1,Laurawly/tvm-1,Laurawly/tvm-1,dmlc/tvm,dmlc/tvm,dmlc/tvm,Laurawly/tvm-1,tqchen/tvm,tqchen/tvm