misc: updated shabang for python script

The default python on MacOS doesn’t have an alias to python2.
The official python version supported in gem5 is Python2.7.

This patch updates the shabang according to the version required in gem5.

Change-Id: I9533c0f7858b5b3cab0ef101be1ee5cd718105b0
Reviewed-on: https://gem5-review.googlesource.com/c/15375
Maintainer: Andreas Sandberg <andreas.sandberg@arm.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Andreas Sandberg <andreas.sandberg@arm.com>

misc: Update #!env calls for python to explicit version

In some newer Linux distributions, env python default to Python 3.0. This
patch explicitly uses "python2" instead of just "python" for all scripts
that use #!

Reported-by: Sanchayan Maity <maitysanchayan@gmail.com>
Signed-off-by: Jason Lowe-Power <jason@lowepower.com>

style: remove trailing whitespace

Result of running 'hg m5style --skip-all --fix-white -a'.

Make qdo work with oar. I don't know if this catches every case, but it appears
to be working at the moment.

Updated Authors from bk prs info

Bump up NFS wait time in qdo (since this has been causing
problems in pool regressions).

util/qdo:
Bump up hardcoded NFS wait time from 45 sec to 90 sec (and
print threshold from 10 sec to 30 sec). Would be even
nicer to make these cmd-line params, but nobody would use
them anyway.

Qdo should kill its subordinate qsub more aggressively
on a timeout.

util/qdo:
Qsub needs a kill -9 to die; kill -15 doesn't cut it.

Fix qdo job name setting.

util/qdo:
Don't automatically set qsub job name, as this causes qsub to fail
if the job name is too long or otherwise unsuitable.

Add qdo options for setting the PBS job name and destination queue.

util/qdo:
Add options for setting the PBS job name and destination queue.

Fix for qdo & new pool node build.

util/qdo:
unset PROMPT_COMMAND in shell in case system sets
it for us.

Support for compiling and testing on pool via 'qdo' script.
For this to work qdo must be on your path. I've copied it into
/usr/local/bin on zizzer.

build/SConstruct:
Add BATCH and BATCH_CMD options to support compiling/testing
on pool via qdo.