If we have a postponed spill, the temp we create at ip is no longer
the spilled temp and therefore is affected by the thrsw injection.
Fixes corruption in the additive blending animation demo from
Three.js.
Fixes: f3c3228522 ('broadcom/compiler: do not rebuild the interference graph after each spill')
Reviewed-by: Alejandro Piñeiro <apinheiro@igalia.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/15112>
c4a78a2d2a