Merge branch 'hack-scalability-sched-and-ordering-check' into '177-stack-exhaustion-in-check_variable_access_ordered'

Hack scalability sched and ordering check

See merge request !407

codegen: Ensure lower and upper slabs are distinct

Closes #215

See merge request !405

See #215.

When specifying split_iname with both lower and upper slabs, we need
to ensure that for loops shorter than the split length only one of the
two peeled slabs is run. Do so by ensuring that the upper slab is
conditioned on being larger than the end of the lower slab.

Fixes #215.

iupd should depend on yoink for deterministic code generation

See merge request !403

Move import to top level

See merge request inducer/loopy!402

[schedule]: schedule_as_many_run_insns_as_possible not performing correctly in the case of parallel_inames

Scheduling goes from 177s to 82s

Merge branch '177-stack-exhaustion-in-check_variable_access_ordered' into '177-stack-exhaustion-in-check_variable_access_ordered'

Don't recompute insn_ids_to_try if nothing changed

See merge request !401

This accounts for 10% of codegen time for sumpy m2l 3d order 6

June monster maint

See merge request !399

Empty ndrange enqueue

See merge request !396

Fix the default shape of loopy.TemporaryVariable

See merge request !354