broadcom/compiler: disallow tsy barrier in thrsw delay slots

broadcom/compiler: disallow tsy barrier in thrsw delay slots

A TSY barrier becomes effective at the point of the next thread switch,
so if we have one coming after a previous thread switch we need to
be careful not to emit it in its delay slots, or we would be effectively
moving the barrier earlier than intended.

Fixes simulator assert crash in:
dEQP-VK.graphicsfuzz.two-for-loops-with-barrier-function

Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13468>