tests: Add a timeout to getremotetime

tests: Add a timeout to getremotetime

The helper is meant to check if the local binary is younger than the
remote binary (on gem5.org). If the call fails it is giving up and
it is just using the local regression (producing a warning).
The code is not handling the blocking behaviour of the connection:
simulaton might stall indefinitely
The patch is addressing this by providing a 10 seconds timeout.

Change-Id: I8f9c2e555c9a55d850a66d02f8e55f56ceda2ca3
Signed-off-by: Giacomo Travaglini <giacomo.travaglini@arm.com>
Reviewed-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/24531
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>