Port new 1.11 behavior for associative varargs

I think this is related to issue #96.

Calling a variadic function that contains argument destructuring fails with the following exception:
Unhandled Exception: Invalid argument(s): Index out of bounds

Example:

(defn one [& {:keys [a b]
              :or {a "a" b "b"}}]
  (dart:core/print (str a b)))

  (one) ;=> ab
  (one nil) ;=> ...Index out of bounds...
  (one {}) ;=> ...Index out of bounds...
  (one {:a "x"}) ;=> ...Index out of bounds...
  (one {:a "x" :b "y"}) ;=> ...Index out of bounds...


(defn two [a & {:keys [b c]
                :or {b "b" c "c"}}]
  (dart:core/print (str a b c)))
  
  (two "x") ;=> xbc
  (two "x" nil) ;=> ...Index out of bounds...
  (two "x" {}) ;=> ...Index out of bounds...
  (two "x" {:b "y"}) ;=> ...Index out of bounds...
  (two "x" {:b "y" :c "z"}) ;=> ...Index out of bounds...

Start by reproducing the one and two examples and compare the behavior with issue #96 and the referenced Clojure 1.11 behavior. Done means associative variadic destructuring works for nil, empty maps, and partial or complete maps, producing the expected strings without an Index out of bounds exception.