Reland "Add feature to determine if host architecture is 64-bit in llvm-lit"

A member of config was removed in this patch which resulted in errors I
didn't expect. Removing config.host_arch will take more work some I'm
readding that field.

Differential Revision: https://reviews.llvm.org/D39465

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@317289 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed