Optimize Sparse setIdentity and add a unit test
Optimize Sparse setIdentity and add a unit test

Zefz/eigen,ROCmSoftwarePlatform/hipeigen,pasuka/eigen,TSC21/Eigen,TSC21/Eigen,Zefz/eigen,TSC21/Eigen,toastedcrumpets/eigen,ROCmSoftwarePlatform/hipeigen,Zefz/eigen,ROCmSoftwarePlatform/hipeigen,toastedcrumpets/eigen,pasuka/eigen,ROCmSoftwarePlatform/hipeigen,pasuka/eigen,ritsu1228/eigen,TSC21/Eigen,toastedcrumpets/eigen,ritsu1228/eigen,ritsu1228/eigen,ritsu1228/eigen,Zefz/eigen,toastedcrumpets/eigen,pasuka/eigen,pasuka/eigen,ritsu1228/eigen