Benchmarks now run in user-mode.

   - Jump to main performed by eret.
   - Nano trap handler added.
   - FinishTest refactored to perform SYS_exit, placed in util.h.
   - Only SYS_exit with test_result=1 results in a passed test.
   - Any other exceptions/syscalls/test_results end program with FAILED test.
   - PCR status set to S64/U64 if compiled in 64b.
Merge branch 'master' of github.com:ucb-bar/riscv-tests