nir: CL size/align of bool (b1) should be 1, not 0
Without this, nir_lower_vars_to_explicit_types ends up producing a scratch_size of 0 if there are any function_temp bools. I expect they should get removed via optimizations later on, but it's a simple fix to avoid having to try to prematurely optimize.
With this fix, we pass the geometrics test.
/cc @bbrezillon @daniels