Python 3 uses 'exec(code, globals)' instead of 'exec code in globals'. Switch to the newer syntax since it is supported by Python 2.7. Also, move check_tracing out of main to work around a bug in Python 2.7. Change-Id: I6d390160f58783e1b038a572b64cdf3ff09535fa Signed-off-by: Andreas Sandberg <andreas.sandberg@arm.com> Reviewed-on: https://gem5-review.googlesource.com/c/15986 Reviewed-by: Jason Lowe-Power <jason@lowepower.com>