feat(kernel): make sure U is the maximal universe

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/simplifier): statically check (conditional) equations (aka rewrite rules) to verify whether we can skip type checking when using them in the simplifier

Signed-off-by: Leonardo de Moura <leonardo@microsoft.com>
feat(library/simplifier): statically check (conditional) equations (aka rewrite rules) to verify whether we can skip type checking when using them in the simplifier