Code modification introduced for benchmarking

[nestordemeure]

This branch introduces a number of modifications that were useful for benchmarking.

In particular:

• having the TOAST_FUNCTIME read its value instead of considering any value true (this is useful when switching from true/1 to false/0 inside a script),
• updating the jax_accel_assign_device function to deal properly with gpu oversubscription (several process using the same gpu)