[OpenMP] Fixing OpenMP/driver.c failing on 32-bit hosts
The changes made in D88594 caused the test OpenMP/driver.c to fail on a 32-bit host becuase it was offloading to a 64-bit architecture by default. The offloading test was moved to a new file and a feature was added to the lit config to check for a 64-bit host.
Reviewed By: daltenty
Differential Revision: https://reviews.llvm.org/D89904