util: clean up and extend style checker
util: clean up and extend style checker

Added a new Verifier object to check for and fix spacing
between if/while/for and following paren.

Restructured Verifier class to make it easier to add
new subclasses, particularly by using a global list of
verifiers to auto-generate command line options and
simplify the invocation loop.

KuroeKurose/gem5,rjschof/gem5,HwisooSo/gemV-update,gedare/gem5,cancro7/gem5,rallylee/gem5,rallylee/gem5,gedare/gem5,powerjg/gem5-ci-test,rjschof/gem5,TUD-OS/gem5-dtu,cancro7/gem5,KuroeKurose/gem5,sobercoder/gem5,qizenguf/MLC-STT,KuroeKurose/gem5,qizenguf/MLC-STT,powerjg/gem5-ci-test,KuroeKurose/gem5,gem5/gem5,qizenguf/MLC-STT,aclifton/cpeg853-gem5,gem5/gem5,powerjg/gem5-ci-test,sobercoder/gem5,Weil0ng/gem5,SanchayanMaity/gem5,powerjg/gem5-ci-test,HwisooSo/gemV-update,qizenguf/MLC-STT,HwisooSo/gemV-update,KuroeKurose/gem5,TUD-OS/gem5-dtu,rallylee/gem5,qizenguf/MLC-STT,HwisooSo/gemV-update,aclifton/cpeg853-gem5,powerjg/gem5-ci-test,briancoutinho0905/2dsampling,Weil0ng/gem5,powerjg/gem5-ci-test,aclifton/cpeg853-gem5,powerjg/gem5-ci-test,gem5/gem5,rallylee/gem5,TUD-OS/gem5-dtu,aclifton/cpeg853-gem5,TUD-OS/gem5-dtu,gem5/gem5,SanchayanMaity/gem5,Weil0ng/gem5,SanchayanMaity/gem5,gedare/gem5,rjschof/gem5,TUD-OS/gem5-dtu,gedare/gem5,cancro7/gem5,briancoutinho0905/2dsampling,briancoutinho0905/2dsampling,SanchayanMaity/gem5,qizenguf/MLC-STT,gem5/gem5,Weil0ng/gem5,aclifton/cpeg853-gem5,sobercoder/gem5,briancoutinho0905/2dsampling,briancoutinho0905/2dsampling,gedare/gem5,SanchayanMaity/gem5,gem5/gem5,KuroeKurose/gem5,rjschof/gem5,Weil0ng/gem5,TUD-OS/gem5-dtu,HwisooSo/gemV-update,briancoutinho0905/2dsampling,rallylee/gem5,cancro7/gem5,sobercoder/gem5,briancoutinho0905/2dsampling,rjschof/gem5,HwisooSo/gemV-update,HwisooSo/gemV-update,cancro7/gem5,rallylee/gem5,aclifton/cpeg853-gem5,sobercoder/gem5,cancro7/gem5,cancro7/gem5,sobercoder/gem5,qizenguf/MLC-STT,gedare/gem5,sobercoder/gem5,Weil0ng/gem5,SanchayanMaity/gem5,aclifton/cpeg853-gem5,rjschof/gem5,KuroeKurose/gem5,rallylee/gem5,rjschof/gem5,gedare/gem5,TUD-OS/gem5-dtu,Weil0ng/gem5,SanchayanMaity/gem5,gem5/gem5