[JITLink] Update BuildingAJIT tutorials to account for API changes in r358818.

DynamicLibrarySearchGenerator::GetForCurrentProcess now takes a char (the global
prefix) rather than a DataLayout reference.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@358820 91177308-0d34-0410-b5e6-96231b3b80d8
2 files changed