Change QEMU cpu to arm1026
Move thread test under #ifndef LIBCXXABI_SINGLE_THREADED
Move call to sleep under #ifndef LIBCXXABI_SINGLE_THREADED
Add file forgotten in previous two commits
Clean up *.out after test run
Add wrapper to QEMU tests

This solves a pretty significant testing bug where tests were silently failing.
The wrapper is needed because qemu doesnt pass through the exit status of the
individual kernels, so one needs to provide signal handlers and an exit handler
to print out failure on anything other than exit(0).
Rearrange error message