Issues with wp.static and max unrolling

[hsalehipour]

This issue can be easily reproduced on main branch and running the windtunnel_3d example or any other example with more than 3 BCs.

• add wp.config.max_unroll = 3 to the beginning of the file.

You will get this error:

warp.codegen.WarpCodegenError: Error while parsing function "kernel" at /home/hesam/REPOs/XLB_refactored/XLB/xlb/operator/stepper/nse_stepper.py:299:
    _f_post_stream = apply_bc(index, timestep, _boundary_id, _missing_mask, f_0, f_1, _f_post_collision, _f_post_stream, True)
;Error while parsing function "apply_bc" at /home/hesam/REPOs/XLB_refactored/XLB/xlb/operator/stepper/nse_stepper.py:214:
            if wp.static(self.boundary_conditions[i].implementation_step == ImplementationStep.STREAMING):
;Error evaluating static expression: name 'i' is not defined. Make sure all variables used in the static expression are constant.