add llvm-toolset-7.0-libomp-devel to Dockerfile.centos7.clang7 for TR
add llvm-toolset-7.0-libomp-devel to Dockerfile.centos7.clang7 for TR

QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD,QuantamHD/OpenROAD,The-OpenROAD-Project/OpenROAD,QuantamHD/OpenROAD,QuantamHD/OpenROAD