QNX requires its own TESTRUNNER script in order to SSH to the QEMU guest
and run the tests. Simplify it a lot and fix the way it passes arguments
so that they retain spaces and quotation.
Also wrap it with the generic TESTRUNNER script for CI, which is
qt-testrunner.py, so that tests can re-run in case of flakiness.
Delete prefix.sh as the environment variables are now properly set in
the Coin platform config files.
Avoid executing extra chmod commands to make scripts executable,
but use the right Coin instruction for that. For reference, we
use 493 for file mode which equals to 755 in octal, as Coin expects
the file mode in decimal.
Change-Id: Ife4d1caef606f48b92ba1da1cfb14ec0dea11ef2
Reviewed-by: Pasi Petäjäjärvi <pasi.petajajarvi@qt.io>