Fix path to llilcBuild if not specified
Fix path to llilcBuild if not specified

If args.llvm_build is specified and llilcBuild and LLVMBUILD are not,
the path specified by args.llilc_build is None. This fix defaults
llilcBuild to args.llvm_build\tools\llilc if llilcBuild is None.

dotnet/llilc,libengu/llilc,adiaaida/llilc,pgavlin/llilc,swaroop-sridhar/llilc,russellhadley/llilc-original,mmitche/llilc,libengu/llilc,libengu/llilc,richardlford/llilc,swaroop-sridhar/llilc,mmitche/llilc,russellhadley/llilc-original,AndyAyersMS/llilc,dkorolev/llilc,dkorolev/llilc,russellhadley/llilc,JosephTremoulet/llilc,libengu/llilc,manu-silicon/llilc,JosephTremoulet/llilc,tempbottle/llilc,pgavlin/llilc,BruceForstall/llilc,mmitche/llilc,kyulee1/llilcjit,swaroop-sridhar/llilc,richardlford/llilc,marksantos/llilc,russellhadley/llilc,adiaaida/llilc,AndyAyersMS/llilc,mmitche/llilc,richardlford/llilc,BruceForstall/llilc,erozenfeld/llilc,tempbottle/llilc,erozenfeld/llilc,dotnet/llilc,erozenfeld/llilc,russellhadley/llilc,manu-silicon/llilc,dotnet/llilc,russellhadley/llilc-original,tempbottle/llilc,adiaaida/llilc,JosephTremoulet/llilc,dkorolev/llilc,marksantos/llilc,kyulee1/llilcjit,marksantos/llilc,BruceForstall/llilc,erozenfeld/llilc,pgavlin/llilc,AndyAyersMS/llilc,kyulee1/llilcjit,russellhadley/llilc-original,manu-silicon/llilc