since totalInstructions() is impl'ed by all the cpus, make it an abstract base class.
since totalInstructions() is impl'ed by all the cpus, make it an abstract base class.

cancro7/gem5,kaiyuanl/gem5,joerocklin/gem5,briancoutinho0905/2dsampling,powerjg/gem5-ci-test,powerjg/gem5-ci-test,qizenguf/MLC-STT,gem5/gem5,briancoutinho0905/2dsampling,Weil0ng/gem5,joerocklin/gem5,gedare/gem5,aclifton/cpeg853-gem5,rallylee/gem5,TUD-OS/gem5-dtu,zlfben/gem5,joerocklin/gem5,briancoutinho0905/2dsampling,powerjg/gem5-ci-test,markoshorro/gem5,kaiyuanl/gem5,KuroeKurose/gem5,gem5/gem5,gedare/gem5,kaiyuanl/gem5,gem5/gem5,powerjg/gem5-ci-test,zlfben/gem5,KuroeKurose/gem5,gem5/gem5,zlfben/gem5,TUD-OS/gem5-dtu,sobercoder/gem5,Weil0ng/gem5,kaiyuanl/gem5,SanchayanMaity/gem5,cancro7/gem5,yb-kim/gemV,briancoutinho0905/2dsampling,joerocklin/gem5,gedare/gem5,aclifton/cpeg853-gem5,rjschof/gem5,KuroeKurose/gem5,austinharris/gem5-riscv,KuroeKurose/gem5,markoshorro/gem5,HwisooSo/gemV-update,zlfben/gem5,rjschof/gem5,SanchayanMaity/gem5,sobercoder/gem5,briancoutinho0905/2dsampling,cancro7/gem5,gedare/gem5,samueldotj/TeeRISC-Simulator,yb-kim/gemV,aclifton/cpeg853-gem5,rallylee/gem5,markoshorro/gem5,markoshorro/gem5,rjschof/gem5,sobercoder/gem5,KuroeKurose/gem5,Weil0ng/gem5,yb-kim/gemV,Weil0ng/gem5,austinharris/gem5-riscv,samueldotj/TeeRISC-Simulator,aclifton/cpeg853-gem5,samueldotj/TeeRISC-Simulator,rallylee/gem5,yb-kim/gemV,SanchayanMaity/gem5,TUD-OS/gem5-dtu,sobercoder/gem5,samueldotj/TeeRISC-Simulator,KuroeKurose/gem5,cancro7/gem5,qizenguf/MLC-STT,SanchayanMaity/gem5,rallylee/gem5,kaiyuanl/gem5,samueldotj/TeeRISC-Simulator,markoshorro/gem5,KuroeKurose/gem5,kaiyuanl/gem5,powerjg/gem5-ci-test,rallylee/gem5,gedare/gem5,qizenguf/MLC-STT,zlfben/gem5,gem5/gem5,joerocklin/gem5,qizenguf/MLC-STT,qizenguf/MLC-STT,austinharris/gem5-riscv,qizenguf/MLC-STT,cancro7/gem5,Weil0ng/gem5,austinharris/gem5-riscv,yb-kim/gemV,TUD-OS/gem5-dtu,HwisooSo/gemV-update,rallylee/gem5,samueldotj/TeeRISC-Simulator,sobercoder/gem5,yb-kim/gemV,powerjg/gem5-ci-test,SanchayanMaity/gem5,Weil0ng/gem5,HwisooSo/gemV-update,gedare/gem5,briancoutinho0905/2dsampling,HwisooSo/gemV-update,rallylee/gem5,cancro7/gem5,aclifton/cpeg853-gem5,rjschof/gem5,gedare/gem5,yb-kim/gemV,markoshorro/gem5,austinharris/gem5-riscv,yb-kim/gemV,samueldotj/TeeRISC-Simulator,TUD-OS/gem5-dtu,rjschof/gem5,TUD-OS/gem5-dtu,gem5/gem5,austinharris/gem5-riscv,zlfben/gem5,gem5/gem5,SanchayanMaity/gem5,rjschof/gem5,briancoutinho0905/2dsampling,cancro7/gem5,HwisooSo/gemV-update,HwisooSo/gemV-update,SanchayanMaity/gem5,joerocklin/gem5,rjschof/gem5,sobercoder/gem5,zlfben/gem5,aclifton/cpeg853-gem5,TUD-OS/gem5-dtu,aclifton/cpeg853-gem5,powerjg/gem5-ci-test,austinharris/gem5-riscv,joerocklin/gem5,markoshorro/gem5,qizenguf/MLC-STT,sobercoder/gem5,kaiyuanl/gem5,joerocklin/gem5,HwisooSo/gemV-update,Weil0ng/gem5