Argument Relevance for Synthesis Conjectures (#1311)

Argument Relevance for Synthesis Conjectures (#1311)

* Initial work on conjecture-specific symmetry breaking.

* More infrastructure, working on process term.

* Flattening.

* Process defs

* More setup

* Fixes.

* Sketching

* Generalize to inference of argument definitions.

* More, separate conjunct processing per synth function.

* Single occurrence variables.

* Assign relevance.

* Document, connecting.

* Connecting to grammar construction.

* Enabled, add regressions.

* Fix regressions.

* Clang format.

* Add regress1, minor.

* Fix

* Two passes.

* Fix

* Note

* Improve check match, make single var occurrence more conservative.

* Add regression.

* Clang format

* Minor comments

* Update regression to new option.

* Undo grammar cons changes.

* Enable irrelevant args.

* Improvements.

* Format

* Minor