local rewrite for apply to a let-bound rest list

local rewrite for apply to a let-bound rest list

* module/language/tree-il/peval.scm (peval): Add a special-case inlining
  pattern for apply to a let-bound rest arg that preserves effect
  ordering.

* test-suite/tests/peval.test ("partial evaluation"): Add a test, and
  update an older test with a better result.